Research On M Method Design And Key Technologies Of Bearing Diaphragm Wall

In recent decades, the development of underground space of more high-rise buildings in urban areas has made deep pits increased in number, in scale, and in depth as well, so as to diaphragm wall is more widely used as retaining structure. unfortunately, it rarely used as main body structure, because the bearing mechanic of diaphragm wall cannot been found yet, and some other problems such as the waterproofing of its juncture, the connection between diaphragm and floor, et. In this case, the diaphragm wall with big rigidity coefficient wastes after the main structure finished, which has blocked the further applications of diaphragm wall. So, as a example of the pit of Jiangsu Procuratorate Office Building, which takes diaphragm wall as basement external wall, load-bearing wall and retaining wall, correlative resolution on diaphragm wall design and key technologies are discussed in this paper.In internal force analysis, deformation calculation and structure design practice of diaphragm wall, many people look for the m value in the m table which has been specified by the codes. The permissible displacement of bearing diaphragm wall is lower than usual, but the range of the values of m is so large that it leads to more error. For this point, On the basis of the in-situ modeling excavation experiment, considering the characteristics of interaction between the diaphragm wall and soil, this paper provide a new method to find out more accurate m value. Three testing piles are used to modifying pit excavation in this program. By the way of modifying the function between the test results of m value and the displacement of testing pile, the author puts the m value into the Lizheng procedure and calculated iteratively, then it would find the most accurate m value.For bearing diaphragm wall, it will bear the upper structure load together with Pile-Raft (Box) foundation, this brings the deformation coordination problem between the two sides. Based on the analysis of trench stability literature and data in both here and abroad, this paper puts forward the calculating method of the interaction of the bearing diaphragm and Wall-Pile-Raft (Box) composite foundation. By means of the analysis of three different composite foundation's interactive patterns, this paper demonstrates the advantage and practicability of the Bearing Diaphragm Wall-Pile-Raft (box) composite foundation. Taking diaphragm wall as basement external wall, load-bearing wall and retaining wall of foundation pit, will bring many challenges in construction of diaphragm, including the stability for slurry-trench of diaphragm wall, accurate location of embedded parts, anti-seepage measures and bearing capacity of underground diaphragm walls. There-for, this paper makes analysis on the complicated stratum, environment, difficulties and possible problems in construction of diaphragm wall, and introduces some key technologies so as to ensure the successful construction of the bearing diaphragm wall.Also, this paper puts the conclusions of research work into practice use of the pit of Jiangsu Procuratorate Office Building, optimizes the engineering design and checks up these conclusions.