Deep foundation pit Special construction scheme for support and earth excavation
2.1 Basic information of the project 2.2 Project scale The elevation of the proposed building ± 0.000 is equivalent to the absolute elevation of 42.95m. There are 1-47 floors above ground and 3 floors underground, and the buried depth of foundation is -14.60m. The natural floor elevation is about 41.50m. 2.3 Surroundings 1) The proposed site is located at the junction of Hexian Road and Linquan East Road, Yaohai District, Hefei City; 2.4 Engineering geological and hydrogeological conditions 2.4.1 Engineering geological conditions 1) The geomorphic unit of the proposed site belongs to Class I terrace. The existing terrain is relatively flat, and the elevation difference is small. The elevation is 20.79~21.53m, and the maximum elevation difference is 0.74m. 2) The survey datum point BM is the intersection of the centerline of Chuangxin Avenue and Wangjiang West Road, with an elevation of 42.378m (Wusong elevation). 3) According to the judgment of field exploration, the bedrock and soil in the site are layered from top to bottom as follows: ① layer of miscellaneous fill (Q4ml) - grayish brown, variegated, slightly wet to wet, loose, poor uniformity, mainly cohesive soil, with plant roots on the surface and silt and humus on the bottom. This layer has poor properties, high compressibility and collapsibility. The layer top elevation is 20.79~21.53m, and the layer thickness is 4.20~9.60m. ② Layer clay (Q4al+pl) - yellowish brown, grayish brown, slightly wet, hard plastic state, containing ferromanganese nodules and a small amount of kaolin, smooth and shiny section, no shaking response, high dry strength, high toughness. This floor is locally distributed in the site (the sales office is missing this floor). ③ Layer clay (Q4al+pl) - yellowish brown, grayish yellow, slightly wet, hard plastic state, containing ferromanganese nodules and a small amount of kaolin, smooth section, shiny, no shaking response, high dry strength, high toughness. This floor is locally distributed in the site (the sales office is missing this floor). ④ Stratum silty clay (Q4al+pl) - brown yellow, slightly wet, hard plastic state, containing ferromanganese nodules and a small amount of kaolin, smooth section, slightly shiny, no shaking response, medium dry strength, medium toughness, low compressibility. This layer is widely distributed in the site, partially mixed with silt interlayer, and the silt is dense. The burial depth of this layer top is 4.20~9.60m, and the layer top elevation is 11.20~17.86m. See "Engineering Geological Profile (Figure 3), Borehole Histogram (Figure 4) and Static Penetration Test Curve (Figure 5)" for the detailed distribution of each rock and soil layer.
