Search

Several fossil woods from Early Cretaceous sediments in Yumen City in northwestern North China Block, China, have been described. They belong to two fossil wood taxa, Piceoxylon yumeniense Zhou, Peng, Deng, Zhang and Yang n. sp. and Protophyllocladoxylon chijinense Zhou, Peng, Deng, Zhang and Yang n. sp. The well-preserved specimens yield secondary xylem with distinct growth rings. Piceoxylon yumeniense exhibits cross-field with taxodioid pits as well as two distinct xylem ray types. The bi- to triseriate rays are characterised by one or two horizontal resin canals with unequal uniseriate ends. Protophyllocladoxylon chijinense Zhou, Peng, Deng, Zhang and Yang n. sp. shows window-like cross-field pits, which are occasionally cupressoid and have uniseriate xylem rays. These fossil wood records improve our understanding of the fossil diversity, floral composition and palaeoclimate of the Xiagou Formation. Palaeoclimatic analysis of the palaeoxylogical assemblage indicates that the northwestern Gansu region predominantly exhibited a warm and wet climate condition, while a brief cooling event may have occurred in the region during the Early Cretaceous.

This paper presented a field study of the reinforced soil wall (RSW) with a geogrid wrap-around facing. In addition to the conventional monitoring content, the strain of the face-wrapping geogrid, which was neglected in most previous studies, was monitored during the construction process. The positional relationship between the maximum vertical earth pressure and horizontally laid geogrid strain was revealed by using the proposed oblique dragging effect. It was found that the strain on the face-wrapping geogrid occurred mainly in the early stage of construction. The oblique dragging effect existing in the flexible RSWs increased the vertical earth pressure and changed its distribution law, resulting in the position of the maximum vertical soil pressure appearing behind the position of the maximum horizontally laid geogrid strain. The horizontal earth pressure at different positions behind the wall was obviously lower than the theoretical result by using Rankine's theory. Also, a modified 0.3H method (where H refers to the wall height) was presented to account for the slope of the wall face, which could be used to determine the potential sliding surfaces for single-stage RSWs and two-tier RSWs with small offset.

To study the mechanical and deformation characteristics of ballastless track subgrade filled with micro-expansion fillers in a water-immersed environment, a physical model of ballastless track subgrade was constructed on a 1:2 scale with expansive andesite fillers. A water immersion test was carried out to model the soaking of the expansive soil foundation caused by rising groundwater. The swelling behaviors of the foundation and their influences upon the mechanics and deformations of the subgrade were analyzed. The lateral swelling pressure of the foundation and the heave of the subgrade obviously increased due to the water immersion, and the values were closely related to the overlying load and lateral restraint. The heave deformation of the double-line ballastless track subgrade showed significant nonuniformity along the lateral direction, causing the track slab to incline with a maximum inclination angle of 1.55×10-3 deg. The heave of the foundation caused a heave in subgrade, but this transferred heave was significantly attenuated. The attenuation rate of the heave at the midline of the track slab was up to 13.38%. The attenuation characteristic can be fully utilized for the anti-heave deformation measures of railway subgrade in expansive soil areas.

The phenomenon characterised by faster growth of the side of trees exposed to sunlight relative to the opposite side is termed plant phototropism. Vertical trunks of silicified wood occur in situ i...

The sheet-pile wall is widely combined with anchoring frame beam to support high slope in Geotechnical Engineering. However, the dynamic characteristics of the sheet-pile wall with anchoring frame beam subjected to seismic excitation are not clear, and the seismic design for such combined structure is still performed based on pseudo-static method or experience. The combination effect will probably induce an interaction between the sheet-pile wall and the anchoring frame beam, which subsequently makes the seismic behavior of such combined structure more complex. In this study, numerical simulation and shaking table test were carried out to investigate the seismic response of the sheet-pile wall with anchoring frame beam by applying Wenchuan ground motion with different amplitudes. The acceleration response, the earth pressure response and the axial stress of anchor were studied in time domain, and the failure mode of structure was obtained by analyzing the element state at different excitation moment. The influence of the excitation amplitudes on the seismic response of sheet-pile wall with anchoring frame beam was also studied regarding the acceleration amplification, the residual earth pressure, the peak earth pressure response, the distribution of anchor stress and the element state of structure. The results show that the acceleration response of sheet-pile wall with anchoring frame beam is less intense while experiencing another equal seismic excitation. The acceleration amplification of anchoring frame beam is greater than that of sheet-pile wall. The residual earth pressure behind sheet-pile wall increases with an increase in excitation amplitude, especially at the top of sheet-pile wall. The peak earth pressure response at the back of sheet-pile wall increases along the wall height, while it presents a decreasing trend behind anchoring frame beam. The anchor is more likely to fail at the beginning of earthquake. The axial stress of anchor increases nonlinearly with an increase in excitation amplitude, and the increasing ratio increases for a larger value of input acceleration. The outer surface of soil deposit experiences repeated tension and shear failures. The element state of structure changes greatly during the intense periods of seismic excitation.

The combined retaining structure is widely used in high slope supporting engineering. In this paper, shaking table test and numerical simulation are carried out on the seismic response of a combined retaining structure where a gravity wall and an anchoring frame beam are used as a lower structure and an upper structure, respectively. The shaking events of Wenchuan, Da-Rui and Kobe ground motions with different amplitudes are applied in both horizontal and vertical directions. The horizontal and vertical acceleration responses are studied in time domain and frequency domain based on shaking table test, and the results are compared with those obtained from numerical simulation. The axial stress response of anchor and the element state of combined retaining structure subjected to earthquake loading are supplemented and studied by using numerical simulation. Both horizontal and vertical acceleration responses near the bottom of frame beam are significantly magnified, which results in a dramatic increment in acceleration amplification. The acceleration response behind the frame beam is more intensive than that at the back of the gravity wall. The high-frequency component of seismic ground motion is weakened by the combined retaining structure, and the vertical acceleration response presents a wider frequency band. The axial stress of anchor is greatly increased by seismic excitation, and the increment is mainly induced within the excitation period of great acceleration amplitude. Shear failure, tension failure, or both are observed at different positions of combined retaining structure during seismic excitation.

Carbon fiber/epoxy resin composites (C/E composites) are wildly used in manufacture of aircraft fuselages and wings in aerospace industry, due to their excellent properties. However, hole making of C/E composites always results in machining damage, such as burr, tearing, delamination and so on. Milling tools with different shapes were used to conduct helical milling experiments on C/E composites. The influence of tool shape on machining damage was analyzed by measuring the damage area of burr, tearing and delamination. And then the feed speed, axial feed per orbital revolution and spindle speed was changed respectively to study the effect of processing parameters on machining damage. The machining damage can be reduced by choosing appropriate tool shape and processing parameters.

The anchoring frame beam is a widely used supporting structure in slope engineering. In this work, the dynamic behavior of anchoring frame beam under earthquake loading was studied by means of shaking table test and dynamic numerical simulation. The results of numerical simulation were compared with the test results in terms of the horizontal acceleration amplification, the vertical acceleration amplification, and the time history of displacement response. The behavior of axial stress of anchor was mainly studied by dynamic numerical simulation. The numerical results are generally consistent with those apparent in shaking table test. The results show that the natural frequency of the supported soil slope presents a decreasing trend during the shaking table test. The soil slope performs an amplification effect on input horizontal acceleration in time domain, and the energy within a frequency range that is around the natural frequency of soil slope is also amplified. Both the horizontal and the vertical acceleration amplifications present an increasing trend with the increase in input acceleration. The acceleration amplification differs greatly under different seismic motions. The frame beam presents a translation displacement together with a rotation around the vertex of frame beam. The residual deformation of frame beam increases obviously with the increase of input acceleration. A larger value of axial stress is observed at the anchor located at the bottom of frame beam. The axial stress of anchor decreases rapidly in anchorage segment, and it tends to zero within a short length under Wenchuan shaking event. The distribution curve of axial stress along the length of anchor presents two peak values after earthquake loading, which is much different from that induced by the self-weight.

The use of hexagonal wire reinforcements to mechanically stabilize the earth works is a recent technique in reinforced soil construction. However, few studies have investigated the mechanical behavior of this kind of reinforced granular soil through large-scale triaxial tests. In this paper, a series of large-scale laboratory unconsolidated undrained triaxial tests were performed on specimens of hexagonal wire reinforced red-sandstone granular soil, and the results were compared to the unreinforced samples to evaluate how the number of hexagonal wire reinforcing layers, water content and degree of compaction affect the measured strength and deformation characteristics of red-sandstone granular soil. The behaviors of hexagonal wire reinforced red-sandstone granular soil were discussed in terms of stress–strain relationship, peak stress strength characteristics, critical strength properties, reinforcement strength ratio coefficient and reinforced mechanism analysis. The failure shapes and the two reinforcement–soil interaction mechanisms of the specimens were revealed. The experimental results show that hexagonal wire mesh reinforcement has an obvious improvement in both strength and deformation of red-sandstone coarse-grained soil, especially under lower confining pressure. In addition, the hexagonal wire mesh reinforcements give an apparent cohesion force to the soil, whereas displaying only a slight increase in the frictional angle. The vertical separation of 20 cm between the reinforcing layers is suitable, and it is suggested that the water content of the red-sandstone granular soil fillings should not exceed the optimum water content and the compaction should not be less than 90%.

Expansive soil is sensitive to dry and wet environment change. And the volume deformation and inflation pressure of expansive soil may induce to cause the deformation failure of roadbed or many other adverse effects. Aimed at a high-speed railway engineering practice in the newly built Yun−Gui high-speed railway expansive soil section in China, indoor vibration test on a full-scaled new cutting subgrade model is carried out. Based on the established track-subgrade-foundation of expansive soil system dynamic model test platform, dynamic behavior of new cutting subgrade structure under train loads coupling with extreme service environment (dry, raining, and groundwater level rising) is analyzed comparatively. The results show that the subgrade dynamic response is significantly influenced by service conditions and the dynamic response of subgrade gradually becomes stable with the increasing vibration times under various service environment conditions. The vertical dynamic soil stress is related with the depth in an approximate exponential function, and the curves of vertical dynamic soil stress present a “Z” shape distribution along transverse distance. The peak value of dynamic soil stress appears below the rail, and it increases more obviously near the roadbed surface. However, the peak value of dynamic soil stress is little affected outside 5.0 m of center line. The vibration velocity and acceleration are in a quadratic curve with an increase in depth, and the raining and groundwater level rising increase both the vibration velocity and the acceleration. The vertical deformations at different depths are differently affected by service environment in roadbed. The deformation of roadbed increases sharply when the water gets in the foundation of expansive soil, and more than 60% of the total deformation of roadbed occurs in expansive soil foundation. The laid waterproofing and drainage structure layer, which weakens the dynamic stress and improves the track regularity, presents a positive effect on the control deformation of roadbed surface. An improved empirical formula is then proposed to predict the dynamic stress of ballasted tracks subgrade of expansive soil.

The lattice anchoring structure is a widely used single-form retaining structure to enhance the stability of soil slope. Meanwhile, the lattice anchoring beam is commonly combined with a gravity wall, namely a combined retaining structure, to support the high slope in engineering practice. In this study, the numerical models for both a single-form lattice anchoring structure and a combined retaining structure were established using FLAC3D code. The Wenchuan ground motions with different amplitudes were applied to investigate and compare the seismic response of the single-form lattice anchoring structure and the combined retaining structure regarding the earth pressure response, the deformation response, the mechanical characteristic of anchor and the element state of structure during earthquake. The numerical results were verified by shaking table test in terms of the dynamic earth pressure response and the axial stress of anchor. Although an intense earth pressure response was observed behind the combined retaining wall, the combined retaining structure was recommended to support the high slope in high seismic intensity region instead of the single-form lattice anchoring structure in view of the deformation of structure, the axial stress of anchor and the failure state of element.

Shaking table test and dynamic numerical analysis are carried out to study the seismic behavior of the gravity retaining wall with anchoring frame beam supporting a steep rock slope (inclined at an angle of 40° with the horizontal) by applying one-directional and bi-directional excitations of Wenchuan motion with different intensities. The horizontal and vertical acceleration responses, the dynamic earth pressure are investigated in shaking table test. A comparative and extensive study is performed in terms of the horizontal and the vertical acceleration responses, the dynamic earth pressure, the axial stress of anchor by means of dynamic numerical analysis with Flac3D code. Results show that both the horizontal and the vertical acceleration amplifications present a dramatic increase at the base of the anchoring frame beam, where the acceleration response is greatly amplified. The bi-directional excitation of Wenchuan motion causes a more intensive acceleration response than the one-directional excitation. The nonlinear behavior of anchoring frame beam is much more obvious than that of gravity retaining wall under earthquake loading. The response of dynamic earth pressure is not in phase as that of the inertial force, and quite a big value of residual earth pressure is induced by earthquake loading. The earthquake loading greatly increases the axial stress of anchor in the free zone. The axial stress of anchor decreases rapidly in anchorage zone and tends to zero within a short length.

The evaluation of seismic passive earth pressure is an important aspect in designing safe retaining walls. In this paper, a slice analysis method is adopted to study the nonlinear distribution of seismic passive earth pressure while considering most of the possible parameters. The closed-form expressions for the resultant force of seismic passive earth pressure, earth pressure distribution, and its application position are obtained. The explicit solution for the critical failure angle of seismic passive earth pressure is proposed by simplifying the relation between the resultant force and the failure angle based on a graphical analysis method. Under certain conditions, the present method correlates with classical passive earth pressure theories. By comparing the present method with test results and previously published solutions, the results are found to be consistent. The influence of the seismic coefficients on seismic passive earth pressure is also studied.

A numerical case study on the seismic behavior of embankment was carried out based on a prototype of earth embankment in Yun−Gui Railway (from Kunming City to Nanning City) in southwest of China. A full-scale model of earth embankment was established by means of numerical simulation with FLAC3D code. The numerical results were verified by shaking table test. The seismic behaviors of earth embankment were studied, including the horizontal acceleration response, the vertical acceleration response, the dynamic displacement response, and the block state of earth embankment. Results show that the acceleration magnification near the embankment slope is larger than that in internal earth embankment body. With the increase of input peak acceleration, the horizontal acceleration magnification presents a decreasing trend. The horizontal acceleration response at the top of embankment is more sensitive to the intensity of ground motion than that at the bottom of embankment. The embankment presents an obvious nonlinear-plastic characteristic when the input horizontal peak acceleration is larger than 0.3 g. The maximum residual deformation occurs in the middle of embankment slope surface instead of at the top of embankment. The upper part of embankment experiences tension failure without shear failure, and area at the bottom of embankment around the symmetry-axis of embankment mainly presents shear failure under the earthquake loading. The tension failure and shear failure repeatedly occur along the slope surface of earth embankment.

Due to the swelling–shrinkage behaviors of expansive fillings, railway subgrade defects in expansive soil regions are prominent, which are difficult to repair, easy to relapse and exist for a long time. Field investigation reveals that some micro-expansive fillings have the potential to construct the railway subgrade and then solve the shortage of railway fillings. However, the swelling characteristics of the railway subgrades filled with the micro-expansive fillings remain unclear. To solve the problem, this paper describes an indoor physical model experiment of a ballastless track-subgrade filled with micro-expansive andesite at 1:2 scale. By simulating the immersion of the foundation (area below the subgrade) in rising groundwater, the effects of the foundation swelling on the mechanical and deformation characteristics of the entire subgrade are analyzed. The results show that the railway subgrade undergoes heave deformation under water immersion, where a significant reduction is observed in the heave deformation from the foundation to the surface of the subgrade. For a double-line railway subgrade, the heave deformation of the foundation increases with horizontal distance from the subgrade centerline. It is also found that the heaves at the track slab and subgrade surface show cyclic fluctuations with a 24-hour cycle due to the periodic variations in the ambient temperature.

The M–O (Mononobe–Okabe) theory is used as a standard method to determine the seismic earth pressure. However, the M–O theory does not consider the influence of soil cohesion, and it cannot determine the nonlinear distribution of the seismic earth pressure. This paper presents a general solution for the nonlinear distribution of the seismic active earth pressure of cohesive-frictional soil using the slice analysis method. A new method is proposed to determine the critical failure angle of the backfill wedge under complex conditions, and an iterative calculation method is presented to determine the tension crack depth of the seismic active earth pressure. The considered parameters in the proposed method include the horizontal and vertical seismic coefficients, wall inclination angle, backfill inclination angle, soil friction angle, wall friction angle, soil cohesion, wall adhesion and uniform surcharge. The classical methods of the M–O and Rankine theories can be regarded as special cases of the proposed method. Furthermore, the proposed method is compared with the test results and previously existing solutions to validate the correctness of the results. Additionally, the parameters׳ effect on the critical failure angle, the resultant force, the application-point position, the tension crack depth and the nonlinear distribution of seismic active earth pressure are studied in graphical form.

In order to study the seismic response of the embankment slopes with different reinforcing measures, shaking table tests were performed on three embankment slope models (i.e., unreinforced embankment slope, 2-layer reinforced embankment slope and 4-layer reinforced embankment slope). Wenchuan earthquake motions and white noise excitations were performed to investigate the change of the model parameters, the horizontal acceleration response, the vertical acceleration response and the dynamic earth pressure response of embankment slopes. A comparison was made on the seismic response among the embankment slopes with different reinforcing measures. The results show that the natural frequency of reinforced embankment slope is larger than that of unreinforced embankment slope, and the reinforced embankment slope is less sensitive to seismic excitation. Horizontal acceleration response is obviously amplified by embankment slope. Horizontal acceleration magnification presents a decreasing trend with the increase of the peak value of input horizontal acceleration, and the decreasing ratio is higher for reinforced embankment slope. The vertical acceleration magnification of reinforced embankment slope is much smaller than that of unreinforced embankment slope, and the nonlinear characteristic of embankment slope in vertical direction is not as obvious as that in horizontal direction. Residual earth pressure is mainly induced at the upper part of embankment slope.

In order to study expansive soil (rock) retaining of Yun Gui railway, based on experience of existing railway, mass in site shear tests, including the tests in condition of underwater and without water, are carried out. In situ lateral swelling force tests of middle-strong and weak-middle expansion soil ( rock ) ,and model tests of lateral swelling force are also carried out. The following results are obtained by tests: water have great influence on the cohesion of expansion soil ( rock ), but its influence on angle of internal friction is limited. A empirical formulas for swelling pressure and moisture content are obtained by tests. The effect of sand cushion to reduce swelling force is obtained by tests.

Based on reinforced earth retaining wall of green gabion which is built at the site of seventh project Shaoxing-Zhuji Expressway, the research for soil pressure in a cross section which locate at the site of K38+398kmare made by field test and numerical analysis. The horizontal and vertical earth pressure are studied in the construction, The pressures between field test and numerical analysis which depend on FLAC3D are rough similar. With increased of height in filling soil, the earth pressures on the wall toe in 3 direction such as horizon , vertical, 45°are increased ,and then gradually come to stability after construction. With increased of height in filling soil, the vertical earth pressures is increased, but the distribution for earth pressure at the same height is non-uniform. The horizontal earth pressure on the back of wall surface increases fast at first then decreases a little, which is a single peak-shaped, it distributes along the wall height in non-linear form, the maximum occurs at 1/3H. The result between field test and numerical model are different, because the flexible wall surface has a great affection on unload.

According to the character and generation mechanism of railway cutting sub-grade diseases, following the needs of YUN-GUI express railway construction, based on the results of laboratory and field test of expansive soil engineering characteristics, developed new waterproof material, designed waterproofing and drainage system of cutting sub-grade, and full-scale dynamic model test was carrying out, a cycle load with 4Hz frequency and 4000 thousand times excitation was imposed on the sub-grade model under three kinds of working condition (dry, raining and underground water rising). The results indicate that: no cracks appeared on the surface of semi-rigid waterproof layer, its durability is good. Waterproofing and drainage system of cutting sub-grade works well under combined action of long term cycle load and complicated environment. Research results possess important engineering reference value.

The deformation of railway embankment is strictly controlled to ensure the safety of train running. In order to study the engineering behavior of railway embankment, simulation analysis on railway embankment with height of 8 m was carried out. Dynamic loads with amplitudes of 0~50 kPa and 0~100 kPa were imposed. The deformation behavior and dynamic stress response of embankment were studied. The results show that the embankment presents attenuation effect on dynamic stress. The static earth pressure near the top of embankment is enhanced, and the static earth pressure at the bottom of embankment is released. The increase of train load will change the failure mode of embankment. The deformation mode of embankment is in subsidence mode when the amplitude of dynamic load is 0~50 kPa, and deformation mode turns sliding mode when amplitude is 0~100 kPa.

To reveal the dynamic behavior of a railway embankment slope subjected to seismic excitation, a shaking table model test was performed on a 1:8 scale embankment slope. Different types of seismic wave of differing amplitudes were applied to study the dynamic behavior of the embankment slope, and white noise excitations were interspersed among the seismic waves to observe the changes of dynamic characteristics of the embankment slope. Residual deformation behaviors of the embankment slope were also investigated. The results of the tests show that the natural frequency of the embankment slope exhibits a decreasing trend and that the damping ratio exhibits an increasing trend. The embankment slope exhibits a significant amplification effect on the input acceleration, and the acceleration response differs greatly when subjected to different seismic excitations of differing spectrum characteristics. The filler of the embankment slope affects the changes of the spectrum characteristics of the seismic wave. The filler performs a filtering effect on high-frequency seismic waves and amplifies the energy of low-frequency seismic waves, especially when the frequency is close to the natural frequency of the embankment slope. A bidirectional excitation creates a greater acceleration response than a unidirectional excitation does. The seismic residual deformation of the embankment slope occurs under the seismic subsidence mode.

In order to study dynamic deformation behavior of green reinforced gabion retaining wall, lab test was carried out and the dynamic loads of 4 frequencies and 4 amplitudes were imposed. The total cycles of dynamic load reached 2 million. Lateral and vertical deformation behaviors of green reinforced gabion retaining wall were investigated, and the main factors which influenced the dynamic deformation behavior and their significance were obtained. Meanwhile, fatigue life analysis on green reinforced gabion retaining wall was made. The results show that dynamic deformation is greatly affected by amplitude and the cycles of dynamic load, not significantly affected by frequency. The maximum lateral and vertical deformation occur in the fifth layer of green reinforced gabion wall. With the increase of train load and train speed, fatigue damage and fatigue life of green reinforced gabion retaining wall can be estimated based on accumulative fatigue damage theory.

Considering the characteristics of high-speed railway settlement requirement, i.e. high precision and strict control after construction, the subgrade settlement of the Wuhan-Guangzhou high-speed rail on the red clay area is calculated by ES method, e-lgp method, triaxial stress method, secant modulus method and field test method. In this essay, the accuracy of various calculation methods has been compared and corrected with the values from loading test. In this process, correction coefficients for various calculation methods have been obtained.

Prediction on red clay foundation settlement was put forward, using hyperbola method, exponential curve method and Hushino method, based on field data. Furthermore, Verhulst model, Gompertz model, Logistic model and Weibull curve were adopted in foundation settlement prediction. Subsequently, variable weight combination method and optimized combination model was studied to get more accurate prediction results. Finally, red clay foundation prediction of high speed railway was proposed.

As geosynthetics is made from polymer, its durability is one of the most important issues people have been concerning. Based on the analysis of data gotten from laboratory, field tests and engineering samplings, the reasons for geosynthetics durability damage are summarized, the injury rules and main factors in various applications are analyzed; after studied the existing durability prediction methods, Support Vector Machine (SVM) theory is applied to predict the durability, and an example is analyzed in which temperature, humidity, UV radiation intensity and the aging time were set as input parameters, residual tensile strength and elongation rate were set as output parameters.

In order to study the engineering behaviors of reinforced gabion retaining wall, laboratory model test was carried out. Cyclic load and unload of five levels (0–50, 0–100, 0–50, 0–200 and 0–250 kPa) were imposed. Vertical earth pressure, lateral earth pressure, deformation behaviors of reinforcements, potential failure surface and deformation behaviors of wall face were studied. Results show that vertical earth pressure is less than theoretical value, the ratio of vertical earth pressure to theoretical value increases nearly linearly with increasing load, and the correlation coefficient of regression equation is 0.92 for the second layer and 0.79 for the fifth layer. The distribution of lateral earth pressure along the wall back is nonlinear and it is less than theoretical value especially when the load imposed at the top of retaining wall is large. Therefore, reinforced gabion retaining wall will be in great safety when current method is adopted. The deformation behaviors of reinforcements both in the third layer and the fifth layer are single-peak distributions, and the position of the maximum strain is behind that determined by 0.3H (Here H refers to the height of retaining wall) method or Rankine theory. Lateral deformation of wall face increases with increasing load, and the largest lateral deformation occurs in the fourth layer, which lead to a bulging in the middle of wall face.

Large-scale field shear tests on ten specimens of the red-sandstone embankment at a highway in Hunan, China, were performed to examine mechanical characteristics and parameters of red-sandstone. The curves of thrust-displacement, failure mode, and shear strength parameters for red-sandstone with different water contents, different compactions, and different grain size distributions were obtained from the tests. A practical procedure of in-situ test for red-sandstone embankment was proposed to normalize the test equipment and test steps. Based on three-dimensional thrust-sliding limit equilibrium method, the formulas for calculating strength parameters of red-sandstone considering three-dimensional sliding surface were inferred. The results show that red-sandstone has typical complete curves of stress-strain, strain softening, which are caused by the special structure of red-sandstone; water content and compaction are important factors for strength and failure mode of red-sandstone; The average value of cohesion and internal friction angle of the specimens calculated by three-dimensional technique are 21.56 kPa and 29.29°, respectively, and those by traditional two-dimensional method are 25.52 kPa and 33.76°, respectively.

We have presented the electronic free energy with respect to the magnetization and the model of the electronic density of states. The expression of the giant magnetoresistance has been obtained by considering the spin splitting of the electronic energy band. Our approach explained the temperature effect on the giant magnetoresistance in magnetic multilayers.

In order to study mechanical characteristic of gabion meshes, engineering properties of reinforced gabion retaining wall and green reinforced gabion retaining wall, tests including air tensile tests of gabion meshes, fatigue and aseismatic tests on gabion structures were carried out. The main tensile mechanical indexes of gabion meshes, fatigue property and seismic behavior of these two gabion structures were obtained. Test results showed: Air tensile curves of gabion mesh showed a zigzag shape; Main factors influencing the dynamic deformation behavior of gabion structures were amplitude of dynamic load, vibration times and so on, and vibration frequency had no significant influence; In fatigue tests, the maximum accumulated lateral deformation occurred in the third layer for reinforced gabion retaining wall, and the fifth layer for green reinforced gabion retaining wall; Accumulated deformation ratios of gabion structures were less than 1% under fatigue load; Both of these two gabion structures were excellent aseismatic structures, and they could bear earthquake action with seismic intensity of eight.

In order to study interface friction characteristics between reinforcements and red sandstone, pullout tests were carried out. Three reinforcements were chosen: 2.2 mm gabion mesh, 2.7 mm gabion mesh and 70RE geogrid. The pullout coefficient, cohesion and friction angle of these three reinforcements were obtained. The curves of pullout friction coefficient and normal stress, shear stress and pullout displacement were established. Test results showed: Pullout friction coefficient decreased nonlinearly with the increase of normal stress; When the pullout displacement reached a certain value, shear stress tended to be stable, and most of which presented a peak value; Pullout coefficients of different reinforcements differed greatly; Double twisted hexagonal gabion mesh had better interface friction characteristic than geogrid; The smaller the diameter of gabion mesh was, the better the interface friction characteristic would be; In general, the pulling-out process of reinforcements could be divided into three stages: initial stage, developing stage and yield stage. During the test, special clamping system was installed to limit lateral deformation of specimen.

To study the extract process of Cyclic adenosinemonophosphate (cAMP) in Ziziphus jujuba.CAMP was extracted with water, separated and purificated by ion exchange and silica gel G column chromatography.Thin layer chromatography (TLC) of the extracts and control cAMP showed the same Rf 0.75; The UV-absorption of the extracts and control cAMP had maximal absorb peak at 260 nm and the least absorb value at 230 nm; Infra-red spectrum of the extracts was indistinguishable from that of control cAMP; Retention time of the extracts by high-performance liquid chromatography (HPLC) determinate was 5.237 minute,unsettled impurity peak,content was 97%. Control cAMP was 5.350 minute,their retention time were of little difference.Chemistry structure of this extract with that of control cAMP is the same.