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Copyright of Chinese Journal of Applied Mechanics is the property of Chinese Journal of Applied Mechanics Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transportation Science & Technolgy is the property of Transportation Science & Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to understand the mechanical response and failure characteristics of anchored fractured coal body under cyclic dynamic load, the dynamic load impact test of anchored fractured coal under cyclic impact dynamic load was carried out by using the split Hopkinson pressure bar test system. The effects of cyclic dynamic load times and dynamic load impact strength on the stress-strain curves, bolt axial force and macroscopic failure of anchored fractured coal were analyzed. The results show that with the increase of dynamic load strain rate, the strength of anchorage specimen increases, but with the increase of dynamic load impact times, the strength of anchorage specimen decreases. When the impact input energy is constant, with the increase of impact times, the internal cracks of coal gradually expand or even fail, and the limiting force of bolt on coal expansion decreases. Under high energy impact, the bolt cannot hinder the initiation and expansion of the internal cracks in the anchored fractured coal body, and the overall instantaneous failure of the anchored coal body is prone to occur.

Copyright of Engineering Mechanics / Gongcheng Lixue is the property of Engineering Mechanics Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The service environment of buried gas pipeline is complex, and the service safety of pipeline is seriously threatened by the landslide geological disaster. Using the ABAQUS finite element software, the damage behavior of the buried polyethylene (PE) pipeline under the lateral landslide load was simulated. The effects of landslide parameters (displacement of landslide mass), pipeline buried depth and internal pressure on the mechanical properties of PE pipe were discussed. The results show that the maximum displacement, the maximum Von-mises stress and the maximum principal strain of the PE pipe are all located in the axial cross-section symmetry plane of the pipe. The maximum Von-mises stress of the pipeline increases with landslide displacement rising. The final yield point of the pipeline is located at the bottom of pipe. The main reason for this condition is attributable to the flattening deformation of the pipe cross section. When the pipeline does not yield, the maximum Mises stress first decreases and then increases with the increase of internal pressure, and the maximum principal strain increases with the increase of internal pressure. The maximum Mises stress and maximum principal strain increase with the increase of burial depth. [ABSTRACT FROM AUTHOR]

Copyright of Railway Construction Technology is the property of Railway Construction Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of High Pressure Physics is the property of Chinese Journal of High Pressure Physics Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Rainfall infiltration greatly affects the stability of the surrounding rock in the construction of water tunnels in loess areas. The unsaturated seepage theory and numerical simulation method were used to study the deformation and seepage field evolution of the surrounding rock under the coupling influence of extreme rainfall infiltration and the excavation disturbance of loess gully area tunnel, and the coupled flow-solidity analysis was carried out through the Plaxis3D model to analyze the mechanical properties of the surrounding rock and the initial support process in the construction of Xin'ao method under rainfall infiltration. The results show that the higher the rainfall level is, the larger the pore water pressure change of the surrounding rock is, and the more unfavorable it is to the stability of the surrounding rock, rainfall infiltration and excavation disturbance will accelerate the redistribution process of seepage and stress fields in the soil layer. Based on the catchment characteristics of the trench, the water content of the surrounding rock of the tunnel shows a stepwise increase in the first 5~10 d, and the maximum deformations at the top of the arch, the waist of the arch, and the toe of the arch are 17. 8 mm, 28. 2 mm, and 24. 6 mm, with maximum shear deformations at the top, waist, and toe of the arch, 24. 6 mm, the maximum shear stress is 150. 6 kPa, 182. 5 kPa, 175. 3 kPa, rainfall end about 15~20 d perimeter rock deformation rate gradually reduce convergence to a specific value, but the stress of the perimeter rock continues to increase, in order to avoid plastic deformation of the perimeter rock, so can be carried out in the 15~20 d of the second lining support. The results of this study can provide reference for the safety control of tunnel construction in loess gully area during extreme rainfall. [ABSTRACT FROM AUTHOR]

[Objective] With the ongoing urbanization in China, the frequency of heavy-duty vehicles traversing buried pipelines is steadily increasing. Therefore, it is of paramount importance to investigate the mechanical response patterns of buried pipelines subjected to heavyduty vehicle rolling in order to ensure the safety of oil and gas pipelines. [Methods] Field tests were conducted to investigate the rolling of heavy-duty vehicles on a buried X70 pipeline. Strain gauge technology was employed to gather pipeline response data and summarize the response patterns of soil pressure and axial stress. Additionally, an ABAQUS software-based finite element simulation model was established to simulate the soil-pipeline interaction using a nonlinear contact model. The vehicle load was simplified as the dead load of a moving plane source, and a DLOAD subprogram was developed to implement the loading. Subsequently, simulations were conducted based on the test conditions. [Results] The results demonstrated a negligible deviation between the simulated and tested values of the additional axial stress in the pipeline. Furthermore, the simulated distribution patterns of soil pressure and axial stress aligned with those observed in the tests, thus the response patterns of soil pressure and axial stress were verified. Based on the verified finite element model, the impact of six parameters, i.e.,vehicle load, vehicle speed, pipe diameter, pipe wall thickness, fill height, and pipeline internal pressure, on the axial stress of the pipeline was explored through simulation by employing a single-variable approach. [Conclusion] The topsoil pressure and axial stress at the section beneath the crawler belts on both sides are higher than those at the central section. Conversely, the bottom axial stress is lower than that at the central section. Augmenting the pipe diameter, pipe wall thickness, or fill height can diminish the additional axial stress induced by vehicle rolling on the pipeline. However, altering the vehicle speed and pipeline internal pressure does not yield significant effects on the axial stress.The obtained mechanical response patterns of the buried pipeline can be used as a reference for evaluating the safety margin of pipelines under heavy-duty vehicle rolling.

Copyright of Transportation Science & Technolgy is the property of Transportation Science & Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to study the influence of diameter on the performance of basalt fiber-asphalt mixture, AC-13 asphalt mixtures mixed with basalt fibers with diameters of 7, 16 and 25 μm were designed and prepared. Rutting test, uniaxial penetration test, low temperature trabecular test, immersion Marshall test and freeze-thaw splitting test were used to study its road performance. Ideal cracking test and dynamic modulus test were used to test its mechanical properties. The results show that the diameter of basalt fiber has a great effect on the improvement of various performance indexes of asphalt mixture. The optimum oil-stone ratio of asphalt mixture increases slightly with the decrease of basalt fiber diameter. Under the same fiber content and fiber length, the smaller the fiber diameter, the larger amount of fibers, and the richer the reinforcement network. Therefore, the 7 μm diameter basalt fiber has the most significant improvement effect on the high and low frequency dynamic modulus, medium and low temperature crack resistance and high temperature deformation resistance of asphalt mixture. The findings of the present work provides reference for the further design of basalt fiber asphalt mixture. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Ordnance Equipment Engineering is the property of Chongqing University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Ordnance Equipment Engineering is the property of Chongqing University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The existing analysis methods lack a reasonable explanation for the cracking, deformation response, and the mechanism of fire resistance reduction caused by the internal confinement of the simply supported two‐way reinforced concrete slab with in‐plane constraints under the fire. Therefore, three ‐ dimensional solid finite element models of simply supported two‐way reinforced concrete slab with in‐plane constraints under fire in both temperature field and thermo‐mechanical coupling analysis were established using the ABAQUS software. On the basis of experimental verification, further parameter analysis was carried out to investigate the deflection, stress variation law, and mechanical response mechanism of steel bars and concrete. The results show that in the case of fire, the in‐plane constraining force weakens the inverted arch effect and tensile film effect of the plate, resulting in a significant decrease in fire resistance. An increase in unidirectional and two‐way in‐plane constraints, aspect ratio, and load ratio will shorten the duration of the inverted arch effect and tension membrane effect stages of plate. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Applied Mechanics is the property of Chinese Journal of Applied Mechanics Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The gabion mesh is an essential part of gabion-protection structures, which is extensively used in the fields of civil engineering and hydraulic engineering. The quasi-static tensile tests were numerically implemented by establishing a three-dimensional model of the gabion mesh and based on the Abaqus finite element software. The numerical implementation process was described, the simulation results were discussed and analyzed, and verified with physical test results. Firstly, the constitutive model parameters of the mesh material were explored and calibrated to ensure the applicability to numerical simulations. Further, the energy history of the mesh system was analyzed and the reliability of the numerical results was demonstrated. The comparison between numerical simulation and physical test results show that the former well reflects the mechanical characteristics of the gabion mesh under the corresponding working conditions, which lays the foundation for the subsequent in-depth study of the gabion structure. [ABSTRACT FROM AUTHOR]

In order to analyze the effect of pipeline-soil action on the gas pipeline crossing under the soil landslide, the pipeline route selection in the landslide affected area was discussed. Based on smooth particle hydrodynamics and finite element coupling method (SPH-FEM), the force analysis model of pipeline under landslide was established. From the design point of view, the position of pipeline laying was comprehensively considered, the influence of pipeline wall thickness, buried depth and other factors was discussed, and the force deformation characteristics of pipeline under large soil deformation were analyzed. Based on the results, some suggestions are provided for pipeline routing optimization in landslide area. Results show that for the thrust-type landslide, when the pipeline is laid in the sliding mass, the stress and displacement of the pipeline at the leading edge of the sliding mass are small, and the damage of the pipeline at the posterior border is more likely. When the thickness of the pipeline wall is increased, the bearing capacity of the pipeline can be effectively improved, but with the increase of the buried depth, the effective yield strain of the pipeline increases first and then decreases. When the pipeline is laid outside the landslide, the stress of the pipeline located at the leading edge of the landslide is less than that at the posterior border, and it presents different stress states, which meet the safety of operation. At the same time, the increase of wall thickness can reduce the stress of the pipeline. The conclusions can provide suggestions for pipeline routing optimization in landslide area in the design stage, which has certain engineering significance and application value. [ABSTRACT FROM AUTHOR]

Copyright of Transportation Science & Technolgy is the property of Transportation Science & Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Natural Gas Industry is the property of Natural Gas Industry Journal Agency and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Architecture & Civil Engineering is the property of Chang'an Daxue Zazhishe and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

When a gas explosion occurs in a mine, the explosion shock wave can damage the water storage dam, leading to a large amount of water gushing out of the goaf, and even causing gas water coupling disasters. Therefore, the stability of artificial dams under extreme conditions is of great significance for mine safety. Currently, there's a lack of research on the mechanical response features of underground artificial dams propagating with gas explosion shock waves. In order to solve the above problems, the LS-DYNA software is used to simulate the impact of gas explosion in roadways on the mechanical properties of artificial dams. The stress state, deformation, and stress features of the explosion facing side, loess interlayer, and explosion backing side are studied. The dynamic response process of artificial dams under the action of gas explosion shock waves in roadways is analyzed. The analysis results of the load distribution on the surface of the artificial dam indicate that when an explosion occurs inside the roadway, the explosion load on the explosion facing surface of the artificial dam is unevenly distributed. At the same time, in the intersection area of various underground structures, the reflected overpressure has a significant strengthening effect due to the convergence and superposition of reflected shock waves. With the rapid release of explosive energy, the impulse loading time history curve of the central measuring point on the explosion facing surface exhibits a three-stage change feature. When the gas volume is 200 m3, the maximum impulse of the central measuring point on the explosion facing surface can reach 0.04 MPa·s within 500 ms of explosion. The results of deformation and stress analysis on the surface of the artificial dam indicate that within 0-500 ms, the central part of the explosion facing surface is always under compressive stress. The maximum lateral displacement of the central node is 0.319 mm. Due to the effect of cutting, the artificial dam is subjected to tensile stress around it, where the maximum tensile and shear stresses occur. The dynamic response of the loess interlayer is in the order of 'compression - compaction - plastic deformation - pressure transfer', during which the loess plays a buffering role, with a maximum displacement of 0.067 5 mm. The wall of the explosion backing side undergoes mechanical response due to the compression of the loess interlayer. But the stress is relatively small, and the outer wall is basically in a safe state.

Copyright of Journal of Mine Automation is the property of Industry & Mine Automation Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To investigate the deformation characteristics of the invert heave in shallow buried mudstone tunnels, a new model test method was proposed and used to simulate the expansion of the surrounding rock beneath the invert by forced displacement loading. This allowed for a systematic analysis of the stress and deformation characteristics of the lining caused by the expansion of the surrounding rock beneath the invert, as well as the failure characteristics of the surrounding rock. The results show that after the mudstone tunnel experienced the invert heave due to the expansion of the surrounding rock, there are significant changes in both the stress distribution of the lining and the pressure distribution of the surrounding rock. The outer side of the arch foot and the inner side of the invert exhibited circumferential tensile stress, which increase the likelihood of tensile failure. Compared with other parts of the lining, the arch foot and the invert has a more significant mechanical response to the expansion of the invert, and with the increasing expansion, the stress difference between the arch foot and the invert gradually increased. Based on the instability state of the surrounding rock, the variation of the surrounding rock pressure is divided into three stages: initial growth, intermediate stability, and rapid growth in the final stage. In the rapid growth of the final stage, the vertical convergence value of the tunnel increased rapidly, the stress growth rate of the lining increased, and the damage to the invert intensified. The expansion of the surrounding rock beneath the invert made the surrounding rock on both sides of the tunnel more prone to instability. The research method and related results might provide a useful reference for optimizing the structure design of mudstone tunnels. [ABSTRACT FROM AUTHOR]

Copyright of Guangdong Architecture Civil Engineering is the property of Guangdong Architecture Civil Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of China Sciencepaper is the property of China Sciencepaper and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to study the mechanical properties of the composite pavement, a finite element model of the composite pavement was established based on the overlay reconstruction project of an airport in the central plains region. Through the established composite pavement monitoring system, the mechanical response of the pavement with the action of the target aircraft type was extracted and compared with the simulation data to verify the rationality of the model. With the action of moving load, the mechanical response of pavement considering different types of aircraft, different interlayer bonding states and different horizontal forces was analyzed. It was found that with the action of B737-800, B767-300ER and B777-300ER, the maximum shear stress of asphalt overlay appeared in the upper layer, and with the increase of the number of rounds, the mechanical index of pavement gradually increased, in which the transverse tensile strain at the bottom of asphalt layer and the tensile stress at the bottom of cement concrete slab changed significantly; With the increase of interlayer bonding coefficient, the pavement mechanical index showed a decreasing trend, and its influence degree gradually decreased along the pavement depth direction; When there was emergency horizontal braking force, the maximum shear stress between asphalt layers increased by 11. 84%, the maximum transverse tensile strain at the bottom of asphalt layer increased by 6.05%, and the longitudinal tensile strain increased by 9. 68%. [ABSTRACT FROM AUTHOR]

Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

For the prominent problem of joint breakage after asphalt pavement pothole repair, a three-dimensional finite element model of asphalt pavement pothole was established by finite element software, and the stress change law of asphalt pavement pothole interface under half-wave sinusoidal load and moving uniform load were analyzed, and the distribution law of temperature field and stress field of pothole repair interface under periodic variable temperature condition were calculated. The results show that the asphalt pavement pothole repair interface is mainly subject to compression and shear, and the alternating stress waveform is the main factor that causes damage to the pavement repair area. Due to the influence of temperature stress, joint cracking and downward extension trend are easily formed on the surface of repaired area. The greater the daily temperature difference is, the greater the temperature stress at the interface of asphalt pavement repair area is. [ABSTRACT FROM AUTHOR]

Copyright of Engineering Mechanics / Gongcheng Lixue is the property of Engineering Mechanics Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

With the acceleration of urbanization, more crossings of roads and pipelines appear, which poses some threat to the safety of pipeline operation. Taking X65 pipeline as the research object, the mechanical response of pipelines under three types of dynamic loads, namely no-load, half-load and full load, was studied through field tests. A parameterized numerical calculation model considering the nonlinear pipe-soil interaction was established, and the accurate simulation of vehicle dynamic loads was realized, which indicates that the error between the numerical calculation results and the test results is within 5%. On this basis, the influence of vehicle weight, pipe diameter, wall thickness, internal pressure and other factors on the axial mechanical response of the pipelines was further investigated. The results show that the overall vertical bending deformation and local deformation are caused by the rolling compaction of heavy trucks. Meanwhile, the axial compressive stress applied to the top of pipelines and the axial tensile stress caused by the Poisson effect of internal pressure offset each other, so that the axial stress at the top of the pipeline decreases. However, the axial tensile stress at the bottom and side of the pipeline are superimposed with that generated by Poisson effect of internal pressure, which increases the axial stress applied to the bottom of pipeline. Therefore, increasing the diameter, wall thickness and buried depth of pipeline can reduce the influence of rolling compaction of heavy trucks on the pipeline. Besides, the weight of heavy trucks has the greatest influence on the axial stress of the pipeline, generally less than 100 MPa.

In order to explore the mechanical response law of different coal rock proportion combinations under true triaxial load, the cube specimens with different combination methods were prepared. The true triaxial test was carried out with the field measured stress evolution as the loading path to explore the mechanical response and deformation characteristics of different coal rock proportion combinations under the stress path, and the pure coal and rock samples were added as the reference for comparative analysis. The results show that the strength, elastic modulus and deformation resistance of coal and rock samples under true triaxial compression are significantly higher than those under uniaxial compression. The mechanical parameters and peak strain of coal rock combination are between coal sample and sandstone sample, and the strength and elastic modulus of specimen are negatively correlated with the proportion of coal thickness. However, with the increase of coal seam thickness, the decreasing trend of the two is not the same. The elastic modulus decreases almost in equal proportion with the increase of coal seam thickness, while the decreasing rate of strength with the increase of coal seam thickness gradually decreases. The reason is that the heterogeneity of coal is more prominent than that of sandstone. The peak strain does not change monotonously with the increase of coal seam thickness. The peak strain of ternary combination is larger than that of binary combination. Under triaxial loading, the difference between mechanical parameters and deformation characteristics of coal rock and rock coal composite specimens is very small, which is considered to be caused by the heterogeneity of coal rock material.

Copyright of Transportation Science & Technolgy is the property of Transportation Science & Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transportation Science & Technolgy is the property of Transportation Science & Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Formation collapse is one of the common geological hazards for the buried long-distance pipelines. In order to study the mechanical response law of the buried steel pipelines under continuous collapse, experiments and numerical simulations of buried steel pipelines under continuous collapse were carried out, the deformation and stress changes of the buried steel pipelines during continuous collapse were analyzed, and the theoretical calculation results of pipeline mechanics under the collapse geological hazards were checked. The research results show that, in the case of collapse in a small area, the deformation and stress of pipelines increase continuously with the collapse area enlarged, and the displacement and stress in the middle of the pipelines are maximized. When the collapse area is expanded to a certain extent, the soil collapses completely, the pipelines are suspended, the displacement of the pipeline is reduced, the stress of the pipe is released greatly, and the maximum stress position of the pipelines changes from the middle to the point near the collapse boundary of the pipelines. The calculation results of the pipeline stress under the collapse geological hazards are greater than the experimental and simulation values if the friction or cohesion are considered based on the gravity, which are of more guiding significance. Further, the reasearch results could provide effective guidance to pipeline protection.

Copyright of Guangdong Architecture Civil Engineering is the property of Guangdong Architecture Civil Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In practice, the reservoir granite will experience the coupling process of high temperature and water cooling shock during dry hot rock mining. The granite was heated and cooled at room temperature and water cooling respectively, and ultrasonic test, uniaxial compression test, XRD, scanning electron microscope and other tests were carried out to explore the impact of high temperature and cooling mode on the granite damage characteristics. It is found that high temperature leads to the increase of volume, decrease of mass, decrease of p-wave velocity, decrease of elastic modulus, and decrease of compressive strength of granite. The physical and mechanical properties of granite deteriorate rapidly at 500℃-700℃. In micro, high temperature leads to the formation of micro-cracks, and water cooling treatment promotes the cracking and propagation of micro-cracks. Macroscopic water-cooled granite has lower physical and mechanical properties and higher ductility and ductility. [ABSTRACT FROM AUTHOR]

In order to analyze the reasonable level and use of high-modulus asphalt concrete in the full-thick asphalt pavement, based on the typical all-thick asphalt pavement structure of Shandong Province. The numerical model of full, thickness asphalt pavement structure was constructed, and high-modulus asphalt concrete was placed in the lower layer, the botlem base layer, the base layer, the base layer + bottom base layer, the lower layer + bottem base layer and without high modulus asphalt concrete, the differences in mechanical response indicators under various working conditions was analyzes. Taking mechanical response improvement rate to determine the rational layer of high modulus asphalt concrete, and verifie the orthogonal test. The results show that the mechanical response has improved under the fact that the operating conditions is increased, and the high modulus asphalt concrete settings can significantly improve the structural performance of all, thick asphalt pavement, and it is recommended to be set in the following layers and the base layer is orthogonal experimental analysis, and the high modulus asphalt concrete is reasonable in the lower layer and the base layer. [ABSTRACT FROM AUTHOR]

To solve the deformation control problems caused by underpass construction of tunnel, the project of shield tunneling of Zhengzhou Metro Line 4, undercrossing closely the existing traffic pipe- jacking tunnels, is studied. Numerical simulation combined with field monitoring is used to reveal the deformation law of the existing jacking tunnels during shield tunnel construction. Based on numerical simulation results, settlement control standard of the pipe-jacking tunnel, the allowable joint opening value of pipe-jacking joints and the minimum allowable radius of curvature of the structural line are established. Then the correctness of the numerical calculation results and the feasibility of setting method of the settlement control standard are confirmed by on-site monitoring. The main conclusions are as follows:( 1 ) During the process of the two shield tunnels crossing the pipe-jacking tunnels at an intersection angle of 37°, the vertical settlement curves of the upper pipe-jacking tunnels present asymmetric characteristics, and the settlement curves of the tunnels show some translation and deflection. (2) Compared with the joint opening control standard, the settlement control requirements based on allowable additional curvature of pipe jacking tunnel deformation are relatively stricter. It is suggested that the maximum allowable settlement value of the jacking tunnel under construction disturbance should be 27mm. [ABSTRACT FROM AUTHOR]

Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of China Plastics / Zhongguo Suliao is the property of Journal Office of CHINA PLASTICS and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In view of the problems such as large-scale dynamic disaster, high degree of destruction and difficult prevention and control in deep coal mining, the theoretical analysis method is adopted. Firstly, based on the micro-seismic data of coal and rock mass in the mining process of deep steep coal seam in Wangjiashan Coal Mine, the CMEAS algorithm is used to optimize the micro-seismic network to obtain the optimal network layout. Secondly, the multi-parameter comprehensive early warning index system of micro-seismic is constructed; according to the actual situation of the site, the risk judgment standard of monitoring data in the mining process is analyzed. Finally, under the best micro-seismic network system, based on the field micro-seismic monitoring data, the temporal and spatial evolution law of the vibration of the roof and floor strata and the front coal seam in the mining process is concluded. In addition, the numerical calculation method is used to simulate the change of displacement field and stress field of coal and rock mass in the mining process of the working face, and the activation mode of peripheral faults, thus the mechanical response law caused by the disturbance of deep mining is obtained.

2. 5D woven composites are an anisotropic material, and their compressive performance after impact also shows significant anisotropy. To investigate the effect of off-axis angle on the residual mechanical properties of 2. 5D woven composites after impact, by low-velocity impact and compression tests and ultrasonic C-scan technology, the compressive properties of 2.5D woven composite in the direction of 0° and 45° after impact under different energies were compared employing. The mechanical responses, failure modes and damage mechanism were analyzed, and the effects of off-axis angle on the compression properties of the material after impact were studied. The results show that when subjected to low-velocity impact, the damage forms of the material mainly include matrix cracking, interface debonding and fiber breakage. Under two given impact energies, the compressive strengths of the material in the 45° direction are lower than those in the 0° direction, and as the impact energy increases, the compressive strength of the 0° specimen decreases more obviously. With the increase of off-axis angle, the mechanical response of the material changes from brittleness to ductility. Secondly, the types, locations and paths of compressive failure after impact of the two off-axis angle specimens are different. The 0° specimen is crushed at the end of the specimen and the damage is distributed along the transverse direction of the specimen, while the 45° specimen appears interface debonding and matrix cracking at the impacted region, mainly along the ±45° directions. It has great engineering significance for accurately evaluating the service performance of the materials in the impact-prone environment. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Engineering for Thermal Energy & Power / Reneng Dongli Gongcheng is the property of Journal of Engineering for Thermal Energy & Power and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Restricted by terrain, a large number of roads and railways often appear along the reservoir line and along the river line, and water level changes are an important factor causing landslides on the banks. At present, most of the researches on slope seepage focus on the unsaturated uniform flow, and the study on the non-equilibrium flow of macropore slope is still lagging behind. In this study, the stability factor of unsaturated seepage flow and unsaturated macropore flow slope was analyzed, and the influence law of the factors including water level rise rate (v), hydraulic conductivity in macropores (Ksf), hydraulic conductivity of the matrix-fracture interface (Ksa), the equivalent diffusion distance between two domains (a), and the volumetric fraction of macropore domain (wf) on the stabilization of slope were analyzed by macropore flow model. The results showed that the water content in the matrix area of the slope was close to saturation in the unsaturated macropore flow, and the water content in the matrix domain was obviously less than that in the matrix domain of the slope under unsaturated macroporous seepage with rise of the water level. The hydraulic gradient of the shallow inward slope was obviously larger than that of the unsaturated large pore flow slope under unsaturated seepage. The moisture content in the matrix domain was much larger than that in the macropore domain (up to 18.9 times) at the same location because the permeability coefficient of matrix domain is much smaller than that of macroporous domain. The stability factor of reservoir bank slope decreased first and then increased with the increase of reservoir water level, and it reached the minimum at the same water level (close to the height of the highest storage level) at the same time. Under the same seepage conditions, the stability of unsaturated macropore flow was weaker than that of unsaturated seepage. Reducing Ksf, a, wf or increasing Ksa made the water exchange between the two regions become slow. As the moisture rapidly migrates to the depth of the slope, it caused the groundwater level to rise and the maximal decrease of slope stability was 17.7%. The influence of v, Ksf and wf slope stability was relatively large and equivalent, while Ksa and a were relatively small and they were about half of the former. [ABSTRACT FROM AUTHOR]

Copyright of Tunnel Construction / Suidao Jianshe (Zhong-Yingwen Ban) is the property of Tunnel Construction Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Xinyang Normal University Natural Science Edition is the property of Journal of Xinyang Normal University Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The three-dimensional finite element model was eatablished with the consideration of load transfer efficiency in the old cement concrete pavement. Considering the arrangement of critical load position, the mechanical responses on the composite pavement surface and at the bottom of the overlay for the old cement concrete were calculated under the aircraft loads of B737-300, B767-300ER and B777-300ER. The maximum value of mechanical response and the location of mechanical response were calculated. The results show that the critical load position of the composite pavement is in the middle of longitudinal seam, and the mechanical response of the composite pavement under the load of the mul-tiaxis landing gear is multi-stress peak mode. With the increasing of the number of axes, the mechanical response is increased significantly, and the superposition effect is more obviously in the multipl-axles. The location of the maximum pavement response at the bottom of the asphalt concrete overlay for the old cement concrete appears near the edge of the tire side. [ABSTRACT FROM AUTHOR]

Copyright of Tunnel Construction / Suidao Jianshe (Zhong-Yingwen Ban) is the property of Tunnel Construction Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)