Advanced Materials Research Vols. 594-597

Abstract: The mechanism of dynamic tri-axial test is introduced in this paper and the dynamic responses of silt soft clay at Zhoushan are studied using a dynamic tri-axial test system. The laws of pore pressure build-up of the silt clay are obtained which are affected by the consolidation pressure and dynamic load. The greater the consolidation pressure and the dynamic loading is, the more the build-up of pore pressure is. However, the dynamic load has minor effect on pore pressure build-up under the anisotropic consolidation.

Abstract: The Waste Dump at Guangyue Road in Hongkou district locates in the center of Shanghai and became a success stories for it being transformed Waste Dump into a resort. However, slight landslide on the Waste Dump occurs frequently whenever the typhoon and dramatic storm happened in recent years. Meanwhile the slope protection with vegetation is becoming the most common, efficient and most practical way for conserving water and soil and keeping slope stable. This article descripts the mechanism of slope protection with vegetation and analyses the actual situation of the Waste Dump at Guangyue Road and discusses how to reasonably apply the mechanism of slope protection with vegetation into ameliorating the landslide situation on the Waste Dump.

Abstract: In designing earth structures, various kinds of complex soils and rocks are constantly encountered. These geomaterials exhibit heterogeneous, nonlinear, and anisotropic behavior. A failure criterion for such complicated materials is proposed. This model is highly comprehensive. It characterizes heterogeneity, nonlinearity, and anisotropy simultaneously in one equation. Many classical failure criteria employed in geomechanics and plasticity are its special cases. The material parameters in the proposed criterion may be determined from tests of unconfined compression, uniaxial tension, biaxial compression, and direct shear. The case study illustrates the potential of the proposed model in engineering application.

Abstract: Double reinforced earth retaining wall belongs to flexible structures, so it adapts well to soft foundation deformation. Compared with other forms of retaining wall, double reinforced earth retaining wall is more economic. An experimental study was conducted to assess the earth pressure on the facing of double-sided reinforced earth retaining wall, and its fundamental mechanism was researched. The results indicate that the horizontal earth pressure on the back grows with the increase of the thickness of the filled soil, its value was between active earth pressure and static earth pressure, the strain of the metallic bar increases with increasing load, It was non-linear distribution along the length of the metallic bar. The results providing a basis for design, theoretic analysis and engineering application.

Abstract: The expansive soil behaviour of expansive deformation and shear strength is deeply influenced by humidity condition. Different soil drying rate was set with constant temperature and different relative humidity. When saturated soil samples was dried to the different predetermined water content, the expansion ratio test with the upper load was made. It is shown that in the condition of high relative humidity, the expansion ratio is high. The smaller initial water content and upper load may lead to a larger swelling deformation. When soil samples with different initial water content was fully expanded, the consolidated direct shear tests were made. It is shown that the smaller drying rate leads to the greater shear strength after full expansion. What’s more, the upper load may improve the soil shear strength.

Abstract: Taking the anchor foundation pit of the super-large highway bridge in Yunnan as an example, the stability is studied. Based on the stratum characteristics of the tertiary strong weathered basalts (TSWB) and analysis principle of engineering geology，many aspects including topography and geomorphology, geological structure, geotechnical interfaces, structural characteristics, geotechnical parameters are considered to analyze the engineering geological environment of the foundation pit. Then, the qualitative analysis of stability and possible instability mode are made.

Abstract: The Woshaxi landslide is located on the right bank of Qinggan river which is a tributary of the Yangtze River, which continuously and seriously developed after the impoundment of Three Gorges. Surface investigation showed that there were shearing, tensing and crush-pressing fissures. The monitoring data showed that displacement of lower part was bigger than that of upper, and the sliding because of the reservoir water level decline. The landslide mechanism was towing forward and pushing backward, and towing happened mainly in the prophase, while pushing happened mainly in the anaphase. Heavy rainfall and water level drawdown are the main factors of landslide deformation.

Abstract: Based on the new-style rotary penetration instrument, the rotating-incising-drilling experiment for the hard rock material are tested in this paper. The conclusion is that rotary penetration test can more effectively improve the drilling capacity than cone penetration test using in hard layer such as soft rock、hard loess and so on, and reduce bit pressure without improving the capability of instruments based on the factor that using rotary drilling instead of direct drilling. Further analyses have shown that the qualitative relationships between rotary penetration test data and basic mechanical parameters can be preliminarily obtained.The results establish a foundation for further study of rotary penetration technique using in hard layer.

Abstract: In this article, the discrete element method is used to investigate the coarse particle material close-grained space structure evolutionary process submitted to a vibrating compressive load. 2-D generation algorithm about irregular particle generation and particle contact interface generation was adopted. Irregular particles were randomly generated in the designated categories with this algorithm. The microcosmic material parameters are endowed to irregular particle and pore space. The microcosmic material parameters are also endowed to water. The irregular micro-particles close-grained process was been analyzed under vibrating compressive. The numerical simulation results demonstrate that the coarse-grained soil Irregular particles compacting effect of the simulation results with the actual theoretic situation in the basic line. The Irregular particles were whirligig and movement, location of the rearrangement as a whole to show the close-grained process. The use of discrete element method can be clearly informed that the simulation of the embankment particles in the body vibration. This research offers a new idea and continent method for compaction dense of hydrous embankment.

Abstract: Combined with the silty soil characteristics of the Yellow River alluvial plain and the subgrade filling of Ji-He expressway, the paper discusses silty soil, stabilized silty soil strength and stress-stain characteristics through the indoor triaxial shear test. The results show that the remodeling silty soil has obvious peak, brittle failure, low residual strength after being destroyed and the stress-strain curve shows a softening type in confining pressure 100kPa lower stress level. In the confining pressure 400kPa higher stress level, soil samples peak is not obvious,mainly plastic failure and the stress-strain curve is close to a hardening type. Compared to mixed with 8% lime, stabilized silty soil of mixed with 4% cement and 4% lime shows that the partial stress peak is more obvious when destroyed and the residual strength is drastically reduced and more incline to brittle failure. In different the age, compared to mixed with 8% lime, stabilized silty soil of mixed with 4% cement and 4% lime shows that internal friction angle becomes larger and cohesion improves gradually whose amplitude is much larger than internal friction angle. Therefore, a more effective way to stabilize the silty soil of the Yellow River alluvial plain is to select silty soil mixed with 4% cement and 4% lime.