Analysis Of Influences On The Surrounding High-rise Building Near The Top-down Excavation

In recent years, with continuous development of economy of Hefei City and rapid growth of population in the urban area, construction of subway is crucial. Generally speaking, areas where subway passes through are erected with dense pipeline and important buildings, and construction environment is complicated. The consequences of local damage of important buildings and even losing use functions are serious. Under the prerequisite of ensuring safety of foundation pit, minimization of the influences on surrounding environment by excavation of deep foundation is urgent, and researching influences of reverse building method of deep and large foundation pit on adjoining high-rise buildings is significant.After researching and reading many domestic and overseas documents, this paper takes the new Jiaotong Building in the Southeast of intersection of Metro Line 1 and Metro Line 2 as background, uses MIDAS/GTS to simulate the foundation pit completely, researches ground settlement and building settlement, comparison and analysis are made for field monitoring data to discuss settlement of the adjoining high-rise buildings. Main conclusions of the paper are described as follows:(1)At the horizontal direction, curve of ground settlement is in form of spoon, and settlement value is increased and decreased with the distance from edge of the foundation pit; at the longitudinal direction, settlement value is positively correlated to soil penetration depth of foundation pit; in terms of space, deep foundation of Dadongmen Station of Line 2 has non-linear overlapping influences on DB01.(2)Seen from JCJ01 and JCJ03, the Shengda International Commercial Building is located at the area with great settlement. Seen from whole period of monitoring, there are 4 settlement stages of the Shengda International Commercial Building: homogeneous settlement stage, accelerating settlement stage, differential settlement stage and settlement stabilization stage. During the entire process, buildings involve differential settlement, and shall be noticed during construction.(3)Settlement differences of JCJ01 and JCJ03 are positively correlated to soil penetration depth of foundation pit and cannot be ignored in construction. Compared with ground settlement difference, increasing of settlement difference of JCJ01 and JCJ03 is little, related to pile foundation forms of high-rise buildings.(4) When the column beam slab structure of excavation for foundation pit is constructed each time, settlement value is smaller, so the structure layer inhibits settlement trend.(5)When rigidity of diaphragm wall is increased, settlement of ground surface and building is relatively smaller. If excavation depth is larger, the function of reducing influences on surrounding environment by increasing thickness of diaphragm wall is more obvious.(6)When step-by-step excavation is changed into integral excavation, settlement of ground and building is increased; compared with reduction of diaphragm wall, after integral excavation is used, settlement of ground and building is increased sharply.This paper simulates settlement of ground and building of deep foundation pit of the new Jiaotong Building in Hefei City, discusses influences on settlement of high-rise buildings nearby with reverse construction of deep and large foundation pit, is of certain theoretical and practical significance and provides technical support for the similar projects in the future of Hefei.