MONITORING AND ANALYSIS OF DEEP FOUNDATION PIT WITH DOUBLE ROW PILES SUPPORTING STRUCTURE UNDER COMPLICATED GEOLOGICAL ENVIRONMENT IN ALLUVIAL PLAIN OF THE YELLOW RIVER

A deep foundation pit in Zhengzhou is located in the alluvial plain of the Yellow River. The site soil is mainly composed of silt, silty clay and silty sand, and the geological environment is complex. The proposed building is residential, commercial and underground garage. The foundation pit is about 12.00m deep. The surrounding areas are residential, most of which are seven stories of brick and concrete structures, which are closest to 5.0m. The excavation area is large, the foundation pit is deep, and is close to the surrounding structures. In this paper, by analyzing the construction, surrounding environment and geological and hydrological conditions of the deep foundation pit, the combined support scheme of two row piles and anchor cables is adopted in the near side of the surrounding construction, and the comparison analysis is made in combination with the field monitoring data. The analysis results show that the settlement of the surrounding surface caused by the excavation of the deep foundation pit is small, and the influence radius of the soil excavation on the surrounding surface settlement is roughly in line with the principle of R=2H(H as the depth of the foundation pit). The location of the maximum settlement of the settlement is about 5meters from the top of the foundation pit, and is 0.4-0.5 times the depth of the foundation pit depth of H. The deformation monitoring results of the two rows of piles and the settlement monitoring data of the surrounding buildings are analyzed. The results meet the requirements of relevant design codes. The research in this paper will provide reference for similar projects.