Construction organization for excavation, support and dewatering of 10m deep foundation pit Design
1. According to the analysis of the geological survey report and the relevant construction experience of our company in xx area, the foundation soil condition of this project is relatively poor. The relatively weak ③ silty sand layer series is partially weak and partially saturated in soft plastic shape, which is easy to cause diameter shrinkage and hole collapse during drilling. ⑤ Silty clay mixed with silty soil layer, because it contains more groundwater, and the silty clay layer is weak, hole collapse is easy to occur during drilling; For medium to dense ⑥ silty sand mixed with silt, due to slow drilling construction speed, stress release will occur on the hole wall, which often results in mud inclusion on the pile body; The bearing stratum at the pile end is ⑦ clay layer, and enough attention shall be paid to the construction technology and method during the construction of bored piles. 2. The soil layers involved in foundation pit excavation and enclosure include ① miscellaneous fill soil layer, ② silty soil layer series, ③ silty sand layer; The pit bottom is mainly located in ④ clay layer with poor engineering performance, so the enclosure must be strengthened. 3. The positioning accuracy and perpendicularity of the deep mixing pile construction of this project are strictly controlled to ensure the continuous and uninterrupted lapping, the cement consumption, the water stop effect, and the water stop curtain effect are the key to the success of this foundation pit. During the construction of deep mixing piles, the amount of gunite and the overlapping length must be controlled. 4. The positioning accuracy and perpendicularity shall be strictly controlled during the construction of cast-in-place piles in this project. 5. There are many construction personnel of various types of work on the same site, so personnel management should be strengthened and the relationship between various types of work and teams should be well coordinated. 6. Since the underground water level of the project is high, the drilling speed shall be well controlled during the construction of uplift piles. The whole construction process is carried out in the open air. Therefore, the construction progress is inevitably affected by natural factors such as wind, rain and temperature. Full consideration shall be given to the construction plan and technical measures.
