The Model Experimental Research Of The Rectangle Diaphragm Wall For Longdong Region Loess

With the development of science technology, construction equipment improvement and closed diaphragm wall construction technology improvement, the closed diaphragm wall is application more and more widespread.with its high bearing capacity, high stiffness, low cost advantages in bridge foundation. Our country western the vast loess area soil, vertical well, water with a small,the low of underground water level, the vertical excavation construction convenient, easily into the groove, suitable for closed diaphragm wall foundation. But at present our country still did not have a reliable and convenient application programs and design method.This paper summarizes the domestic and foreign related of the closed diaphragm wall foundation application examples and calculation methods, summed up the impact of its important influence factors. On this basis, in combination with Hall of Gansu province traffic scientific research projects, relying on the West Changfeng highway building overpass bridge. Through indoor test of undisturbed soil sample, the test field of physical mechanical properties of intact loess. Through field test, numerical simulation analysis of the main research content of the following respects.(1) It analyzed that through the vertical load test, the closed diaphragm wall with a solid wall based on the characteristics of the load settlement, between the resistance of the end wall and the wall side friction load sharing ratio variation, soil limit frictional resistance, the core soil stress mechanism. The modei test results show that:Closed diaphragm wall foundation wall vertical bearing capacity is smaller than the entity; With the increase of vertical bearing capacity load ratio by lateral friction resistance to bear70%mainly composed of end resistance assume change; Side friction resistance to play with the wall week soil parameters and the change of wall soil relative displacement; Under the action of vertical load, the wall impact on the surrounding soil.(2) Through the horizontal loading test, research of closed diaphragm wall foundation horizontal force deformation and horizontal load closed diaphragm wall foundation on surrounding soil are studied. The modei test results show that:Underground continuous wall is horizontal loaded of wall lateral soil resistance changes in two stages, when the load is less than the maximum bearing capacity of soil resistance performance for large small, but the load exceeds the maximum bearing capacity performance for the next big small; When the load is less than the maximum bearing capacity, the wall top horizontal displacement of linear variation, when the load exceeds the maximum bearing capacity, the top of the wall displacement increased dramatically.(3) Through the numerical analysis, the vertical loads of closed diaphragm wall foundation with a solid wall based on the load transfer mechanism; The core soil of closed diaphragm wall foundation resistance situation, as well as the load share ratio with the top of the wall variation in load of distribution rule. Through the horizontal loads of closed diaphragm wall in3D numerical simulation, studies the closed diaphragm wall foundation horizontal force characteristics, as well as the impact on the surrounding soil.