【Haichuan Civil Engineering Issues】Key points for inspection during foundation pit construction
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Regardless of the type of inspection, they are generally divided into document inspections and on-site inspections. Document inspection mainly focuses on the construction plan and relevant process documents. On-site inspection refers to the assessment of the implementation of various quality requirements related to safety measures at the site. I. Construction Plan 1. A specialized construction plan must be prepared for foundation pit works. 2. Such a specialized plan must be reviewed and approved in accordance with relevant regulations. 3. For foundation pit plans that meet the criteria for a certain scale, expert evaluations must also be conducted. 4. If there are any changes around the foundation pit, such as in environmental or construction conditions, the specialized construction plan must be reviewed and approved again
II. Foundation pit support 1. For narrow foundation trenches excavated manually, where the excavation depth is large or there is a risk of slope collapse, support measures must be taken. 2. The slope ratio for natural sloping must comply with the requirements of the specific construction plan and relevant standards. 3. The foundation pit support structure must meet the design specifications. 4. It is necessary to monitor the foundation pit support structure; if horizontal displacement reaches the designated warning level, effective control measures must be taken
III. Dewatering and waterproofing of the foundation pit 1. Effective dewatering measures must be taken if there is groundwater within the depth range of the foundation pit excavation. 2. Drainage ditches must be installed around the edge of the foundation pit and meet the required standards. 3. During slope excavation, dewatering measures must be applied to the top, surface, and bottom of the slope. 4. Drainage ditches and sump wells should be established around the bottom of the foundation pit to remove accumulated water promptly
IV. Trench Excavation 1. Excavation of the underlying soil can only proceed after the support structure has reached the strength required by the design. 2. Excavation must be carried out in layers and sections, as specified in the design and construction plans, to ensure even progress. 3. Effective measures must be taken during trench excavation to prevent damage to the support structure or engineering piles. 4. When machinery is used in soft soil layers, measures such as laying materials like waste soil, sand, and gravel should be taken to harden the ground
V. Safety Protection 1. Protective railings must be installed around foundation pits with a digging depth of 2 meters or more, in accordance with the relevant requirements. 2. Special ladders for construction workers to ascend and descend must be provided inside the foundation pits, and these ladders must meet the specified standards. 3. Covers or fences must be installed at the openings of dewatering wells
VI. Foundation pit monitoring 1. Monitor the foundation pit project in accordance with the requirements. 2. The monitoring parameters must meet the design specifications. 3. The time intervals between monitoring sessions should comply with those specified in the monitoring plan. 4. Monitoring reports must be submitted as required, and their content must be complete. VII. Emergency plans 1. Develop emergency plans for foundation pit projects in accordance with the requirements; such plans should be comprehensive and provide practical guidance. 2. Establish a proper emergency response organization, and stock up on necessary emergency supplies, materials, tools, and machinery.