Applied Mechanics and Materials Vols. 638-640

Abstract: Guizhou section of Chengdu-Guiyang Railway is located in northwestern GuizhouPlateau, which belongs to Chishui River and Wujiang Drainage Area. Thegeologic structures are mainly the fold or fracture in the direction of North-North East, and have Flat rock. Carbonate rocks are widely distributed on the surface of this area. All kinds of karst pronounced,and water and soil conservation is very bad. Rocky desertification is serious, and environmental is sensitive. Karst is one of the main unfavorable geology of control line scheme. In this paper, from the regional geological environment and regional hydrological environment ,analysis of the factors influencing karst has been done. The development regularities of karstis summarized, and the corresponding classification standards are provided. Through the comprehensive analysis of each line program of geological factors,karst geological basis for the route plan is provided .

Abstract: Gushing water in deep well and roadway has become a crucial technique problem which threatens mining safety. Taking advantage of transient electromagnetic, high-density electrical method and a combination of geological analysis, drilling testing analysis, an analytical method for gushing source and path was proposed, and types of gushing water were sorted in light of the cause of formation and governing strategies. Each gushing characters were systematically studied, thus forming the corresponding governing key techniques. Governing methods and main qualification for surrounding rock safety were proposed, with a careful consideration of the surrounding rock safety during grouting. The achievements are widely used in Guotun coal mine in Juye coal field with success, which offers a reference for similar engineering.

Abstract: Through analyzing slide-zone loess porosity microstructure and quantitative analysis, the article can obtain the relation between variational characteristics of slide-zone loess porosity micro-structure and dynamic stress. Experimental results show that slide-zone loess microstructural parameters with load increasing appears a certain laws, and we can use simple linear equation to stand for the relation between porosity quantity or porosity area or porosity morphology ratio and dynamic stress. There is a negative correlation between porosity quantity and dynamic stress, but to other microstructural parameters and dynamic stress, it is a positive correlation. All of these laws are closely related to porosity transformation that forming under axial dynamic stress. It is worth mentioning that porosity fractal dimension with increasing dynamic stress increases, appearing linear correlation. When the confidence coefficient is 0.05, their correlation is well. Synthesizing above study, there is some guiding significance for establishing loess microstructure mechanical model and soil mass microstructural mechanics.

Abstract: In order to obtain the Tibet gravel slope’s response under earthquake, using ABAQUS analysis this kind of slope and get the peak acceleration on the key elements along the slope height. Found that the result can truly gave the max acceleration during earthquake and the acceleration distribution of the slop.

Abstract: The max level sliding distance of Zhu Quedong landslide is 80m; its vertical sliding distance is 50.0m. An the sliding axle, the sliding mass length is about 450.0m, which perpendicular to Changde-Jishou expressway; the leading edge width at hillside foot is about 500m and the sliding mass width along Changde-Jishou expressway is about 430.0m. Its volume is about 2.6×10⁶m3. The direct economic loss is about 3.192×10⁷RMB. According to geology investigation, the geological structures control the landslide: fault F₁and fault F₂ control the boundary of landslide, the stratum attitude controls the slip direction. Rainfall and river erosion are the major factors to cause the landslide. Multiple sliding formed Zhu Quedong landslide outline and there is different failure model in different area. In I_-1 sub region, the failure model is creeping-tensile for slope foot loses support caused by river erosion; in I_-2 sub region, the failure model is slip-buckling-tensile caused by the lateral drag force of I_-1 sub region slipping, in I_-3 sub region, the failure model is slip-tensile with rotation-slide for its foot loses support caused by I_-1 sub region and I_-2 sub region slipping and uneven stacking load cause by subgrade construction, in I_-4 sub region, the failure model is slip-tensile. In II area, the slope failure model is shear deformation by lateral forces of I area slipping. In III area, the slope failure model is slip-tensile because the slope foot loses support caused by I area sliding.

Abstract: By Hainan tropical rainforest area geology, physiognomy, the characteristics of climate, tropical rain forest complex typhoon heavy rainfall weather conditions, and the characteristic of the tropical rainforest landslide occurred, researching and analyzing the relationship of among tropical rainforest landslide, tropical rain forest vegetation destruction the relationship ,the heavy rainfall and human engineering activities. Summed up the vegetation destruction, heavy rains and engineering activities of the three factors of coupling is the most important characteristics of tropical rain forests of landslide, and put forward reasonable tropical rainforest landslide protection and management measures.

Abstract: With the development of Hainan tropical rain forest tourism, the constructions of transport and water conservancy facilities are improving in these areas, which will probably cause landslide for changing the topography of the original slope conditions. In that context, a study is performed to find out the reasons for the landslide in tropical forests areas by employing some examples.

Abstract: The behaviour of pile-groups subjected to lateral soil pressure is a key consideration in establishing the design parameters of pile-groups. In this paper, one representative section of the Chongqing Jiangdong slope is taken as an example. The existence of an arching zone around pile groups for granular and fine-grained soils is first examined using the finite element computer code CORE-3D. Pile load-displacement curves and the arching effect are considered together to explain how the stresses are transferred from the soil to the piles. The key parameters controlling the soil arching effect are centre-to-centre pile spacing (S), thickness of stable soil mass (H), depth (L) of pile embedment, pile diameter (D) and these were studied extensively. An empirical equation summarising the results is presented and the results have been adopted by the designer in practice.

Abstract: In static load test, most of piles do not destroy, the piles still exist capacity, which reduce the reliability index of pile foundation. This paper employs Bayesian Statistic method to update the measured capacity of piles. Meanwhile, based on updating data, the reliability index is calculated considering the destruction of piles. The case study shows that the reliability index of capacity becomes large when the time of pile destruction increases. Therefore, when judging the safety of pile foundation, it is highly necessary to consider the influence of pile destruction on reliability of piles.

Abstract: This paper presents a non-probabilistic method for reliability analysis of cement mixing composite foundations. First, the load transfer mechanism of composite foundations is described. Then a three-dimensional finite element model of cement mixing composite foundation under embankment is built. The settlement of subgrade is analyzed. Finally, a non-probabilistic reliability method is used to investigate the settlement reliability. The results show that the cement mixing composite foundation can significantly improve the compressibility of soft soil.