Advanced Materials Research Vols. 1065-1069

Abstract: Software ABAQUS was carried out to analyze the effect of earth berms on behavior of cantilever retaining structure, and the soil was in modified Cambridge model. The results showed that: in the premise of ensuring the stability of earth berm itself, height and width of earth berm increased reasonably can reduce the horizontal displacement and bending moment of supporting structure, so as to improve the safety of the supporting structure, and save the cost of project.

Abstract: The excavation usually cause the settlement of surrounding soils, which will have a negative effect on the adjacent buildings. To find the effective measures to reduce the surface subsidence,a numerical model which is based on a project example is developed in this paper to analyze the settlement of surrounding soils during the excavation of a deep foundation pit by using FLAC^3D.The influence of excavation on settlement outside the foundation pit is investigated when changing one of the factors which include reinjection pressures、waterproof curtain. The results show that: (1) The settlement of surrounding soils decreases gradually with the increase of reinjection pressures. Moreover ,the settlement with reinjection are around two times the value without reinjection.(2) The settlement of surrounding soils decreases gradually with the curtain depth increases. In the actual projects,we can decrease the settlement of surrounding soils by increasing the reinjection pressures and curtain depth.

Abstract: Laboratory experiment and back analysis are common methods for selecting shear strength parameters. However, every way has its shortcomings. A way combining two methods is used to determine shear strength parameters for Hutoumao landslide. The result can meet the need of project according to comparison experience value.

Abstract: Marine geotechnical investigation techniques provide important support for maritime salvage project. when using the new technology of pile rooting to righting shipwrecks, marine geotechnical investigation can provide a detailed physical and mechanical properties with reasonable parameters, and then use of splines curves and inverse distance weighting method to apply parameters to each pile, then analysis of the vertical uplift and compressive bearing capacity based on API standard, analysis of the level of resistance and strain relations based on P-Y curve method, predict drivability of piles and so on.

Abstract: Based on ABAQUS finite element analysis software simulation, the finite element model for dynamic analysis of rigid pile composite foundation and superstructure interaction system is established, which selects the two kinds of models, by simulating the soil dynamic constitutive model, selecting appropriate artificial boundary.The influence of rigid pile composite foundation on balance and imbalance of varying rigidity is analyzed under seismic loads. The result shows that the maximum bending moment and the horizontal displacement of the long pile is much greater than that of the short pile under seismic loads, the long pile of bending moment is larger in the position of stiffness change. By constrast, under the same economic condition, the aseismic performance of of rigid pile composite foundation on balance of varying rigidity is better than that of rigid pile composite foundation on imbalance of varying rigidity.

Abstract: In order to fully reveal information about landslide displacement, it was necessary to extend a time series to a higher-dimensional state space for the characteristic of univariate time series. However, in order to control the expansion of noise, an appropriate embedded dimension of phase space reconstruction was not the bigger the better. In this paper, based on the displacement time series of landslide, the phase space theory was used to build displacement time series matrix and the entropy theory was used to get the entropy. The embedded dimension of phase space reconstruction could be adjusted according to the change of entropy and feedback of displacement prediction error and a support vector regression model was created via the support vector machine’s learning. The application on Baijiabao landslide indicates that the proposed method achieves a high accuracy and stability of prediction.

Abstract: The aim of this study was to investigate the effect of temperature on adsorption behavior of di-n-butyl phthalate (DBP) in kaoline and montmorillonite. Adsorption isotherms experiments were conducted at 288, 298 and 308 K, respectively. Results showed that adsorption capacity decreased and adsorption intensity enhanced with temperature increased in both minerals. Adsorption amount was larger in montmorillonite than in kaoline. Thermodynamic data indicated the process was a spontaneous and exothermal process and the dominant affection was physical adsorption.

Abstract: In order to analyze the physical and mechanical properties of the stratified mudstone, the specimens are collected from southwest Nanning , Guangxi, China. X-ray diffraction is used to analyze the mineral composition, the high montmorillonite content affects softening and expansion behavior of the mudstone. The strength tests show that the strength of stratified mudstone is low. When weakness layer exists in the mudstone, the strength is controlled by the soft layer. By long-term immersion in water, the strength will be approximately 76% to 85% reduction. The uniaxial compressive strength tests show that the ratio between soft layer and hard layer under natural is 0.17. The ratio between soft layer and hard layer under saturation is 0.10, under air seasoning is 0.42.

Abstract: Based on the similarity theory, rock-like material had been adopted to simulate deep buried marble of Jinping-II Hydropower Station’s diversion tunnel. Specimens which contains different spatial distributions of fractures had been used in the triaxial compression, tension and compression test, and the stress-velocity of ultrasonic P-wave curves were acquired. The result shows that in the triaxial compression test, the velocity of P-wave increased with the axial compression increasing when confining pressure was constant, the increasing rate was firstly swift and then slowed down, the velocity of P-wave increased with the confining pressure increasing when axial compression was constant. In the triaxial tension and compression test, the velocity of P-wave decreased with the confining pressure increasing when axial tensile stress was constant. Under the same stress state, the larger the angle between the propagation direction of ultrasonic P-wave and the fractures, the smaller the ultrasonic P-wave velocity.