Advanced Materials Research Vols. 919-921

Abstract: Micro antislide pile is more and more widely used in the emergent repair of landslide. But systematic and complete understanding about its antislide and failure mechanism is still insufficient; in addition, the theoretical study lags far behind the practical application. Through largesized physical model experiment and numerical simulation, the paper analyses the failure mechanism and failure mode of micro antislide piles in soil slope. The experiment and numerical simulation prove the fine antislide effects of micro piles, which allows large displacement of sliding mass and can delay the collapse of slope effectively, so it is applicable for emergent repair. The deformation of micro antislide pile is “S” shape, which is the tensile failure and shearcompression failure of concrete by bending deformation. At the same time, tensileshear failure happens on the reinforced bars. The largest shear of pile is located on the sliding surface and all the largest bending moment is above the sliding surface. The bending moment on the first row of plies is the largest followed by the third row and that on the second row is the smallest.

Abstract: The artificial island physical and mechanical property of fill index has a great influence on the island stability and the development of displacement. The fill is generally composed of a lot of construction rubbish, industrial waste or the living garbage .We discuss the relationship between shear strength and coarse particle,density relations under different compactness through the experimental study in this paper. The results show that cohesion increases with the content of coarse particles,and compression modulus increases along with the increase of the density. When the content of coarse changed from small to large, compression modulus increases with the increase of coarse grain content at the beginning. When the content of coarse reached 20%, compression modulus with compaction degree increases fastest.

Abstract: The seasonal permafrost is widely distributed in China. Seismic Design Code (GB50011-2010) assumes that the soil temperature is above 0°C, which lacks the analysis of seasonally frozen soil. This article considered various sources of shear wave velocity variability and the frozen depth variability and calculated the ground response spectrums of the sites with seasonal frozen soil. The results shows that when Class1 and Class2 venues with thinner overlying soil and higher shear wave velocities their peaks of response spectrum with frozen soil will higher than that without permafrost. In the design the spectrums with frozen soil need to be calculated independently. In Class 3 and Class4 venues the response spectrums are essentially coincident, so the design only need calculate the spectrums under normal condition.

Abstract: Abstract：Using large-scale shearing device, K0 consolidated-drained triaxial test and isotropiclly consolidated-drained triaxial test under different confining pressures are performed for overburden material of ShuangJiangKou earth dam which relative density is 0.9. And meanwhile, isotropically consolidated-drained triaxial test under different confining pressures are also performed for overburden material of ShuangJiangKou earth dam which relative density is 0.8. The difference of strength and deformation between under under K0-consolidation condition and isotropic consolidation condition and between under different relative density, and the influence of confining pressure, relative density and consolidation condition on the dilatancy of coarse-grained are analyzed. The results show that the strength of K0 consolidated-drained triaxial shear test is slight greater than that obtained by isotropically consolidated-drained test. The strength of coarse-grained soil increases with increase of relative density.The volume strain value of isotropically consolidated-drained triaxial shear test is bigger than that of K00 consolidated-drained test, and the volume strain value decreases with the decreases of relative density. The dilatancy of coarse-grained soil decreases with the increase of confining pressure, and increases with the increase of static lateral pressure coefficient.

Abstract: The paper studies the influences of pore aqueous solution on the swelling pressure of expansive soils through the constant volume swelling pressure experimental experiment. The results indicate that the swelling pressures decrease with the increasing of solution concentration. In the experiment, two specimens made of the same solutions concentration are immersed into solutions with two different concentrations, one less than the solution concentration used to prepare specimen, and the other same to that. The results shows that the swelling pressures of two specimens gained from the experiment are very close. The analysis on the existing state of the pore water shows that the experimental result is agree with the osmotic pressure theory.

Abstract: The Principles of Mohr-Coulomb failure model and hardening and rate dependence are dealt with in detail. Based on Mohr-Coulomb failure model with isotropic hardening, numerical analysis is conducted . The results calculated show that the horizontal displacement and moment of the continuous wall, and the subsidence of surface outside the pit agree with the objective laws during the excavation. The method adopted and those results gained by numerical method may provide reference to engineering practice.

Abstract: Excavation unloading zone corresponds to stress decreased area of slope rock mass after excavation. Quality of slope rock mass in this area will be degraded due to excavation disturbance, and the mechanical parameters of rock mass will be also degraded accordingly. Therefore, determining the range of excavation unloading zone accurately is one of the key factors to ensure the rationality and validity of numerical simulation results of rock slope excavation. In this paper, the range of excavation unloading zone is determined by comparing stress field before and after excavation, choosing stress component perpendicular to excavation face as comparative standard in calculation, which can be calculated by computer program with FLAC software. Stress adjustment of slope rock mass due to excavation is a dynamic and changing progress, so the range of excavation unloading zone is changing during excavation, which can be achieved by a cycling program in numerical simulation. The correctness and usefulness of this method is proved by the calculation results of example analysis.

Abstract: Ultimate lateral bearing capacity of rock mass is the base of the research of laterally loaded drilled shafts socketed in rock mass. The ultimate bearing capacity is often not available because of the limitation of loading ability in field tests. Numerical tests are used here to simulate the drilled shafts socketed in rock mass and expand the load-displacement curve obtained from field tests. Common methods of determining ultimate lateral bearing capacity are also analyzed and compared here. At last, a relatively accurate method of determining laterally loaded drilled shafts socketed in rock mass is recommended.

Abstract: With the environment problems more and more emerged the matters caused by dewatering are set out to be probed and the rule that the ground settlement around a dewatering well presents a funnel shape , is acquainted usually. But in the case of special geology and hydrology due to this paper a new ground settlement pattern presents according to the buildings failure status and the subsequently monitoring results analysis. Namely the ground settlement along the transverse direction to the underground runoff presents V-shape flute profile in the area around the predominant underground runoff. The results also demonstrate that: 1 The foundation type in main building is as same as in the podium building .The main building kept stable while the podium building presented large settlement and inclination and went to failure in final during the construction of the pit. 2 The difference of affecting degree due to dewatering in the environment around the pit is variable and the main affecting zone appears locality and directivity. According to the investigation the most possible main resource of dewatering originates from the river system around to the pit pass by the podium building. 3 Combining the construction process of the pit and the time points of deformation in the building , associability is confirmed between buildings deformation and dewatering on the pit on the ground of excluding the other artificial factors around the building.

Abstract: Composite foundation settlement is affected by many factors, and settlement data is a non-linear changing process with complexity, suddenness and progressive nature and so on. So we must analyze and predict the stability of the foundation settlement. Because empirical mode decomposition (EMD) provides a new way for foundation settlement prediction, we can extract modal signals associated with the foundation settlement mechanisms by decomposing the monitoring data of settlement by EMD and use the support vector machine ( Support Vector Machine, SVM) modal to predict the obtained signal, Calculation results of the modal synthesis and accumulation of foundation settlement, get the evolution of Change with the time of foundation settlement. Combined with the engineering example for the application ,shows that the prediction model has good effect in multi modality support vector, a high degree of agreement with the monitoring values, indicating that this method has a promotional value.