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Through a tunnel-blasting project, the effect of tunnel-blasting vibration has been analyzed from the perspective of vibration energy transfer. The non-linear regression method was used to obtain the prediction equation for blast vibration velocity based on the field blast vibration data. Then, the maximum charge per delay of the blasting construction of the tunnel was obtained through the formula inversion. Based on the traditional Hilbert transform, a novel Hilbert–Huang transform (HHT) analysis method considering Complete Ensemble Empirical Mode Decomposition with Adaptive Noise decomposition (CEEMDAN) and wavelet packet threshold de-noising method has been proposed, the feasibility of which was verified using the field blast vibration signals. It has been proved that the improved HHT analysis method can be used to analyze the influence of the different blasting vibration parameters on the regular distribution of vibration energy. In addition, the dimensional analysis method was used to establish the blasting vibration energy prediction model. The results of this research show that the improved HHT analysis method can solve the problem of modal aliasing caused by the traditional decomposition method, and can obtain the purified main modal components, which improves the adaptability of HHT analysis. In addition, with the increase of the distance between blast area and the maximum charge per delay, the high-frequency energy of the blasting signal gradually weakens, while the dominant energy frequency band diverts to the low-frequency band. The methods and conclusions of this research can provide a certain reference for the controlled blasting construction in similar cases.

To accurately grasp the failure mechanism of surrounding rock in Nanguan deep coal mines, and improve the ability of the concrete filled steel tube support effectively. First, the large size specimens made by rock-like material were compressed under different biaxial loading rates and different intermediate principal stress, meanwhile, the acoustic emission (AE) were used to characterise the crack propagation of the target specimens. In addition, the crack propagation and peeling accurately in the whole progress of uniaxial compression experiment in micro aspects were simulated by using ABAQUS software with cohesive elements in three-dimensional. Finally, the effect of different biaxial loading rates and different intermediate principal stress on crack evolution in large size specimens was analyzed together with the SAEU2S real-time monitoring system of AE behavior characteristics of these specimens. Experimental results clearly indicate that the trend of AE characteristics showed obvious stages when the stress changed by true triaxial testing machine and the rock failure process can be reflected significantly, which proved the efficiency of the proposed cohesive element in ABAQUS.

This paper first analyzes the factors influencing the safe thickness and the broken mechanism of rock between a tunnel and the surrounding concealed caves on the Cheng-gui railway line. Then, based on the analysis of broken mechanism, a comprehensive numerical analysis method, which is based on the Yujingshan Tunnel project, is put forward. This method of analysis is simulated using FLAC3D software to perform three-dimensional numerical simulations for different positions, providing the basis for the subsequent safe thickness analysis and construction scheme design. Actual monitoring and computational results shows the safety distance of the range of the tunnel’s diameter, which proved the rationality and effectiveness of the calculation of the safe thickness between the tunnel and the surrounding concealed caves.

With the exploitation of a large number of coal resources in Western China, the phenomenon of local water shortage has become increasingly prominent. In order to protect water resources, coal mine underground reservoir came into being. In the underground reservoir of coal mine, the stability of artificial dam is often the key to the water storage. In order to enhance its stability, steel structure is often arranged inside the artificial dam and connected with the bolt arranged in the cut, so that the artificial dam and the surrounding rock form a whole and play the role of water storage and blocking together. However, the effect of this reinforcement structure still needs to be further studied. Therefore, this paper takes Wulanmulun mine as the engineering background, mainly uses FLAC3D numerical simulation software to analyze the effect of reinforcement structure, and finds out the relatively reasonable bolt size. The results show that: the artificial dam and surrounding rock are more stable and safe under the reinforcement of bolt, increasing the size of bolt will reduce the displacement and plastic zone range of cut in the side, especially increasing the size of bolt at the top and bottom will have better effect.

This paper first analyzes the tilting reasons of a steel-concrete building in Zhangjiakou city in China. Then, a jacking rectification method which combines the pie-cutting method and the excavation of stress release trench was put forward. This analysis method uses the three-dimensional numerical simulation for soil settlement and vertical displacement and internal force of upper structure in order to assure the safety of the building in the process of rectifying. The analysis case showed that the inclination rate of the building was stable in the process of cutting pie, which proved the efficiency of the proposed method.

SEM tests were conducted on four kinds of typical deep rocks in Meilinmiao Mine, and the micro properties were analyzed. The particles of gritstone are unbroken and particle diameter ranges from 80 μm to 400 μm, and the void between particles is wide. The macroscopic failure of gritstone is caused by breakage of the dung distributed between particles, and potassium feldspars contained in gritstone are not leached. The failure of medium sandstone is caused by micro cracks distributed in sandstone particles, and potassium feldspars are leached seriously, so the pores penetrate each other and there is close hydraulic connection in medium sandstone. The particles of fine sandstone are broken, and the particle diameters range from 60 μm to 300 μm, which determines the pores have good connectivity between particles. The dolomites contained in fine sandstone are corroded, and the micro fracture form belongs to inter-granular fracture. There are no particles and blocks in microstructure of sandy mudstone, but there are diverse micro cracks. The failure of mudstone arises from the extension of micro cracks, and the microstructure is different from the other three kinds of sandstones obviously.

The deformation and failure mechanical mechanism in soft rock roadway is related to the stability of supported tunnels, which is important to coal mine production and construction. By physical mechanics experiments and X-ray diffraction (XRD) tests, the engineering mechanical properties of soft rock, as well as main mineral composition of the surrounding soft rock of Qigou Coal Mine, were obtained. Based on analysis results, a method using bolt-beam-net combination to support was put forward. Mechanical analysis of the support form was done by using the calculation software FLAC3D. Results show that clay minerals of this mine are kaolinite and illite mixed layer, of which the water absorption is relatively obvious and presented mudding characteristic after absorbing water, with the plasticity index of 0.35, with small expansibility, which is weakly consolidated colloid with strong connected force in unit cell. The rock blocks have the characteristics of moisture absorption softening, and the deformation mechanical mechanism of which is with the coexistence of molecular expansive mechanism, colloid expansive mechanism, and weak layer trend type. The calculation results show that the bolt-beam-net support structure makes the bolt, beam, and roof deform compatibly. The beams make the force in the bolt relatively homogeneous, which restricts the displacement of the tunnel roof as well. Finally, using in situ monitoring, the numerical results were verified.

On the basis of the analysis on the disadvantages of the original goal-setting about rock drivage, this paper defined the “life cycle quality”. With project management theory and the Cobb-Douglas function, “quality-cost and quality-price curve model” and the “total cost-period prediction model” were built. Then the goal-setting method of the balance among quality, cost and period of rock drivage was constructed by finding “life cycle cost” through “life cycle quality” using “quality-cost and quality-price curve model” and ensuring period through “life cycle cost” using “total cost-period prediction model” (hereinafter referred to as the “three goals balance method”). “Value contribution” which is the value of the contribution to a mine because of rock drivage, was found in the process of constructing the “quality-cost and quality-price curve model”. An industrial test was done in coal mine A with the research results, staff footage efficiency improved by 24.24%, the period shortened by 14.3%, the “life cycle cost” dropped by 2.09%, the “life cycle quality price” improved by 3.29%, and value contribution increased by 25.3%. The result shows that the new goal method setting on the basis of coal mine profit maximization can ensure construction period. At the same time, it can realize cost and quality objectives and the optimization and balance of relationship among them; rewarding excavation teams by “value contribution” can combine organizational goal with personal goal, it significantly raise the employee’s work efficiency.

By means of the split Hopkinson pressure bar (SHPB) testing system, this paper presents a dynamic constitutive relation of anthracite at a strain rate of e=5–85s−1. Generally, the dynamic stress-strain curve for this kind of anthracite under uni-axial compression has the following four stages: a non-linear loading stage, a plastic yielding stage, a strain-strengthening stage and an unloading breakage stage. Correspondingly, the initial elastic modulus Eb, the yielding strength σs and the ultimate strength σb increase along with an increasing strain rate. The time-dependent elasticity was identified when we analyzed the mechanical properties of anthracite. Based on characteristics of measured dynamic stress–strain curves and an analysis of existing rock dynamic constitutive models, as well as a preparatory simulation, a new visco-elastic damage model has been introduced in this paper. A linear spring is put parallel to two Maxwell units with different relaxation times to express two distinct plastic flows. The damage D is equal to [Eb–E(ɛi)]/Eb, where Eb is the beginning modulus and the E(ɛi) is the slope of a connected line between the origin point and any other point on a tested stress-strain curve. In the new constitutive model, one Maxwell unit with low relaxation time φ1 is used to describe the response of anthracite to a low strain rate, while the other, with a high relaxation time φ2 describes the response of anthracite to a high strain rate. Simulated stress-strain curves from the new model are consistent with the measured curves.

Summary The tilting of buildings not only leads to inconvenience but also causes serious building collapses with heavy casualties and serious social impacts. However, rectification and reinforcement construction method started late in China. Now, this construction pattern mainly depends on sophisticated design techniques, without systematic techniques to reference. Based on the in-depth analysis on tilt reason of a brick-wooden building in Yunnan Province in China and combined with jacking rectification method, the impact pile project, artificial inserting shield engineering for steel box girder project, unbonded prestressed engineering project and concrete filled steel tube reinforcement example. Analyzing the multipoint synchronous lifting process by 3-dimensional numerical simulation in ANSYS finite software. The actual monitoring results showed that the maximum inclination rate was reduced to less than 2.95‰ in the end, and the architectural distortion was stabilized in the process of rectification and reinforcement, which guarantees building safety and efficiency in the process of rectification.