Under The Action Of Overload With Ishinari Gravel Layer Slope Failure Mechanism And The Study Of Stability

With the rapid development of China's economic construction, more and more high-rise buildings rise in urban, meanwhile the pit excavation develops toward deeper and larger. During excavation, sandwich-like layered soil gravel is common to see, and it is usually taken as homogeneous slope for calculation during the design period, which leads the results of calculation to match the reality badly. Therefore, it makes the study of the failure mechanism and stability of sand gravel layered slope under overloading have realistic significance.On the basis of knowing the theory and method of slope stability well, the deformationfailure mechanism, working performance and stability of sand gravel layered slope under overloading action are studied through the method of combining laboratory tests, numerical simulation and theory. Related research results are as follows:1.The law about the change of displacement of the sand gravel layered slope under overloading action is obtained by laboratory model test. Comparing all kinds of working conditions, it is found that the failure model of sand gravel layered slope is local shear failure and the type of the sliding surface is arc plus straight line.2.FLAC is applied to carry out numerical simulation on all the working conditions of laboratory test, which shows that the failure mechanism of various types of conditions consistent with the model test and that the type of the sliding surface is arc plus straight line. By calculating a variety of working conditions, the law that the ultimate bearing capacity and displacement of sand gravel layered slope under overloading action change with the thickness of gravel layer, the positions of gravel layer, the ratio of slope and the loading area is analyzed. What effect the capacity well are the factors, the thickness of gravel layer, the positions of gravel layer and the ratio of slope.3.The permissible velocity field of the sliding surface of the sand gravel layered slope being overloaded is established. The calculation formula of ultimate bearing capacity is obtained by using the limit analysis upper bound method. Comparing the calculated result with the result of laboratory test and the result of numerical simulation indicates that the different value between the formula method and laboratory test is about 10.42 percent, which is of practical engineering value.