Papers by Keyword: Rock

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Authors: Nian Qin Wang, Yao Qiong Xue, Xiao Yu Cheng, Qi Pang
Abstract: The mechanical parameters of rock and soil has an important position in the project, the accuracy of the landslide’s mechanical parameters is very important in landslide stability, displacement forecast and prevention engineering design, compared with the laboratory tests, the in-situ tests have many outstanding advantages, the results are more according with the actual. This article through the in-situ shear test of the celadon and purplish red sandy mudstone which in zhongnan concave, detailed describes the test principle, sample preparation and test scheme, to provide a kind of strength parameters acquisition method, at the same time provide definite reference to the congeniality rock and soil.
Authors: Ming Tian Li, Xia Ting Feng, Hui Zhou
Abstract: Based on the cellular automata of the plane truss structure, a 2D cellular automata model is presented to simulate the fracture of rock at meso-level. Cellular automata are made up of cell, states, lattice, neighbor and rule. Rock is divided into lattice in which each lattice point presents a cell. Each cell is assumed to connect with several cells, which are called as its neighbors, in virtue of truss elements. The truss elements can adopt some different simple local laws, i.e. constitutive law, which may be elastic or elastic-plastic and the simple fracture rule. It also can adopt different mechanical properties, which present their heterogeneity and anisotropy. This model can make full use of the advantages of cellular automata such as its intrinsic parallelism, localization and so on. In the meantime, as a powerful tool to analyze the nonlinear, complex system, cellular automata can be used to study the nonlinear, complex fracture process. The model is used to simulate the direct tensile of the rock plates, the complete fracture process and the stress-strain curves are attained which are accordance with the experiment.
Authors: Yan Yan Cao, Shao Peng Ma, Xian Wang, Zhao Yong Hong
Abstract: Considering with the spatial characteristics of concentrated deformation field caused by the micro-cracks concentration and localization in rock, a new damage variable is defined based on the standard deviation of the strain fields of rock specimen surface during loading. When digital speckle correlation method (DSCM) is used to measure the deformation fields of rock specimen, the damage variable definition in this paper takes great advantages on damage measurement of rock methods. Using the new methods, the damage of rock would be measured for the whole loading process and the experiment is easy to be implemented. The validity of the proposed damage variable is verified by the experimental results on column-shaped marble specimen subject to uniaxial compression.
Authors: Zhong Hu Zhao
Abstract: In order to improve the efficiency of the direct testing machine for rock tension experiments, a new elastic foundation of lower clamper is used to replace the original rigid one. By using this direct tension machine, the complete stress-strain tensile curve of rocks sample was obtained, and the rock mechanical property was studied with this experimental result. Basing comparing the experimental result between the indirect and direct tension experiment, the authors recommend it may obtain the mechanical parameters by direct tension test as well.
Authors: Zhong Ze Xu, Jian Hua Wu, Jin Song Zhu, Wei Dong Xu
Abstract: To obtain the characteristics of rock is one of the most significant methods in reconnaissance in order to make the project camouflaged. This paper, which is based on the former study on digital image processing technique, is mainly about the way to acquire the general and detailed information, such as geographic distribution and specific texture of rock. The technique put forward in the paper is fundamental to carry out reconnaissance, design the project and evaluate the camouflage effect.
Authors: Rui Gao, Ling Qiang Yang, Xiang Dong Wang
Abstract: A numerical implement to simulate the crack propagating process in arch dam and rock base has been put forward. A new remeshing strategy of FEM meshing grid was presented for improving the calculation accuracy and efficiency. In the period of dividing the dam structure and the foundation rock into an appropriate number of discrete subregion (finite elements), the adaptive element was used to divide the original 3-D element into 8 son-elements analogical to its father-elements entirely. Of course the 2-D element was divided into 4 son-elements analogical to its father-elements entirely using the same method. The element shape function was used to solve suspend nodal point. The arithmetic and shape function’s formulation also were put forward. To satisfy the engineering accurate result, the adaptive element was used to divide the son-element or the grandson-element again. In the calculating processor, the arithmetic of adaptive load step was presented. Only one element failures in a load step. So the cracking processor can be found with automatic mesh generation. An arch dam has been as example to validate the method is right and stability. The arithmetic has important theory and utility value.
Authors: Shu Tong Yang
Abstract: Ground anchors have been very practical in a wide range of geotechnical structures. Good bond properties at the anchor-mortar and mortar-rock interfaces can ensure transmitting an applied tensile load to a load bearing structure efficiently. The bond performance between the mortar and rock is necessary to be studied. A push-out test of mortar from rock block can be used to analyze the interfacial properties between the two materials. In this paper, an analytical model is proposed to determine the push-out capacity of mortar from rock block. Based on the deformation compatibility at the interface, the compressive stress in the mortar and the interfacial shear stress at the mortar-rock interface are formulated at different loading stages. By modeling interfacial debonding as an interfacial shear crack, the push-out load is then expressed as a function of the interfacial crack length. In virtue of the Lagrange Multiplier Method, the maximum push-out load is determined. The validity of the proposed model is verified with the experimental results. It can be concluded that if the interfacial parameters at the mortar-rock interface are obtained, the push-out capacity of mortar from rock block can be accurately determined using the proposed model. The proposed solution in this paper would provide a good theoretical basis in evaluating the stability of ground anchors in practice.
Authors: Jian Fu Shao, F. Bourgeois, O. Ozanam
Authors: Peng Yun Li, Li De Wei, Yu Bo Liu
Abstract: The study is still few for the slopes of rock with low permeation,which has interfaces for rain infiltration and no interface for effusion. The stability of slope with rainfall infiltrating under different drain condition is evaluated by the global safety factor, based on the limited equilibrium methods. The following conclusions are obtained: (1) the two rows of drains don’t enhance the value of safety factor very much, and the layout of only one row of drains is advocated;(2) the effect of the system in which drains beat in marlite is better than the system in which drains beat in the breccia;(3) the effect of the system in which drains are designed in the toe of the slope is best, and the spacing of the drains whose diameter is 0.11 m should be less the 8m .
Authors: Yuan Lian Pan, Ying Hui Chen, Yan Chao Ma, Wei Ling Chen, Guang Qi Sheng
Abstract: The shear stress of prestressed anchor cable is unevenly distributed along anchoring length.Based on the load transfer behaviors of bolt,the solutions for distribution of the shear stress in pre-stressed cables are derived.And the mechanical characteristics are discussed for the influences on the shear stress distribution.The calculated values are compared with the results of the filed tests,and good agreements are obtained.
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