Test And Research On Bearing Behavior Of Diaphragm Wall Foundation In Loess Area

The diaphragm wall can be directly used for the foundation of buildings, bearing the vertical and lateral load from the superstructure simultaneously and transferring them to the ground base. This kind of foundation is called diaphragm wall foundation. It is a new kind of deep foundation form which has many advantages, and can substitute traditional deep foundation. However, research on the diaphragm wall foundation which appeared lately is not sufficient, and examples are not abundant. There are extensive loess areas in our country. In loess area, the soil has better orthostatic capacity, fewer moisture content and lower groundwater level, and construction is simple without slurry protection and underwater concrete pouring. So the diaphragm wall foundation is fit to be applied. But there are very few application in our loess areas, because we have no systematic, credible and convenient application programs and design means.For these reasons, test and research achievements, important influencing factors and key problems being solved about bearing behavior of diaphragm wall foundation are concluded in this paper. By on-site vertical and lateral load tests, the vertical and lateral bearing behavior of diaphragm wall foundation are studied, associating the science and technology program of Ministry of Communications and depending on some under construction arched bridge in our loess areas. At last, design means related to the bearing behavior of diaphragm wall foundation are expounded, and some suggestion and improvement are presented associating testing diaphragm wall foundation.Test instrument have been improved before testing. One shaft diaphragm wall foundation is tested under vertical load in self-balanced method. According to the situation and data of test, distribution of axial force, side resistance and tip resistance of wall are analyzed. Q-s curve in test is equivalently transformed, and the vertical ultimate bearing capacity is estimated. One single diaphragm wall is tested under lateral load. According to the situation and data of test, lateral critical and ultimate loads are fixed, and distribution of internal force in the wall and soil resistance is analyzed. The relationship between soil resistance and lateral displacement in different depth and the value of m which is used in our country are calculated.This test is not only the first on-site load test to shaft diaphragm wall foundation in self-balanced method, but also the first on-site large size model load test to shaft diaphragm wall foundation in the loess area in our country.