community Service Centre Construction organization design of deep foundation pit
± 0.000 of the project is equivalent to the absolute elevation of 32.60m, and the bottom elevation of the foundation pit is -10.8m, which is equivalent to the absolute elevation of 21.8m. The excavation depth of the foundation pit is 2.12-9.01m, and the plane of the foundation pit is rectangular; The current project site is high in the west and low in the east, and the ground elevation is between 26.94-31.66m. The site is relatively open, 33.0 meters to the north is the school wall, 13.0 meters to the south is the Gangcheng East Street Green Belt, 75.8 meters to the west is the Yongming Middle School Road, 21 meters to the east is the Goubei Village Access Road, and the middle of the site is a ditch from northeast to southwest. The perennial water in the ditch is mainly the discharge of upstream domestic sewage and surface water. During the construction of the foundation pit, the construction unit diverted the ditch, and the water flow was discharged from the flood discharge ditches on the west and south sides of the site. The depth of the initial phreatic water level measured on the site of the project is generally 3.0~5.0m, and the elevation of the comprehensive stable water level (Yellow Sea elevation) measured after the drilling is completed is 25.80~27.61m. According to the survey geological data, the Quaternary soil layer in the site area is relatively thick with obvious aquifers. The groundwater in the site area is mainly Quaternary pore phreatic water. Quaternary pore phreatic water mainly exists in the upper (1) plain fill, (2) coarse gravel sand, (4) coarse gravel sand and (5) gravel layer. Therefore, it is necessary to take measures to reduce the groundwater level to ensure the normal progress of civil construction. According to previous experience and combined with dewatering checking calculation, the project plans to adopt large diameter tube wells for dewatering. Moreover, the excavation depth of the foundation pit is large, and comprehensive foundation pit support is required.