Field Test And Numerical Simulation Of Earth Pressure Against Multistage Retaining Wall

The multistage retaining walls have been constructed in projects widely and triumphantly with the rapid economic growth. Some researchers have studied the earth pressure in the mentioned retaining structure and found some good results. However, due to the complexity of earth pressure problem,it is lack of a uniform design criterion or a set of calculational rules in multistage retaining structure area. Therefore, researching on the earth pressure in the multistage retaining structure by some made projects is necessarily and urgently.In this thesis, the multistage gravity retaining wall along Shi-Man highway is analyzed by using the method of field test and numerical simulation:(1) In allusion to retaining structure mentioned above,the position of the field test equipments and testing method are introduced in detail, which could be a good reference for such field test of similar project.(2) The horizontal earth presure data are obtainded using field test equipments. With these data, it is found that the distribution of horizontal earth pressure can be described as letter 'R'. The data analysis results also show that with the depth of fill increasing, the earth pressure increases and the position of the action point of the earth pressure is between 0.4H and 0.5H.(3) According to the Coulomb earth pressure theory and the coefficient of static earth pressure formula, the theoretical active earth pressure value and static earth pressure value are calculated with the field test geologic information and the corresponding calculational parameter.Comparing the theoretic value to the field test value, it is found that:as for the each level of the first-step wall, the static earth pressure value can be regarded as the upper design value, for other levels of retaining wall above that level constructed on the retaining wall, active earth pressure value can be considered as the upper design value.(4) A two-dimensional numerical model for the retaining wall is established in ANSYS. By using the method of killing or activating elements, it simulates six different construction processes for the retaining wall.For each of the six simulation test, change rules for displacement and earth pressure of the retaining wall are founded. The details are as follows:when the height of the retaining wall structure increases in the construction process, the top and the bottom of the retaining wall moves differently. The top moves in the direction of fill, while the bottom goes opposite. Meanwhile, the settlement behind the retaining wall decreases when it approaches to the back of the wall. From the top of the slope to the lowest level of the retaining wall, the settlement decrease gradually. As for earth pressure, there exists tensile stress in the fill closely behind the retaining wall. And the tensile stress increases with the construction process. At the same time, there also exists pressure stress in the fill which has a distance from the retaining wall. The longer the distance is, the greater the value of pressure stress will be.(5) Comparing the result of finite difference to the field test,it is found that the multistage reaining wall in shi-man highway is safe.