Engineering geology and hydrogeology conditions, environmental protection requirements, site conditions and foundation pit plane dimensions should be considered comprehensively in the construction plan of foundation pit excavation,The excavation depth, supporting form, construction method and other factors, the water adjacent foundation pit should still consider the highest water level, tide level and other factors.

The excavation sequence of foundation pit should be determined according to the method of stratification, segmentation, block, symmetry, balance and time limit. Before foundation pit excavation, retaining structure, soil reinforcement and dewatering should meet the design and construction requirements.

Construction road layout, material stacking, excavation sequence, excavation method and so on should reduce the adverse impact on the surrounding environment, support structure, engineering piles, etc.

When earthmoving excavators and transport vehicles directly enter the foundation pit for construction, measures should be taken to ensure the stability of the ramp,The slope of the ramp should not be greater than1:8, the width of the ramp should meet the requirements of vehicle driving.

The construction trestle shall be specially designed according to the environmental conditions of the surrounding site, the shape of the foundation pit, the support layout and the construction method; During the construction process, the load of the construction trestle should be controlled according to the design requirements.

Foundation pit excavation shall meet the following requirements:

1, the construction load around the foundation pit and the slope platform should be controlled according to the design requirements; The earthwork of foundation pit excavation should not be stacked in the adjacent building and the surrounding area of the foundation pit, and should be shipped out in time.

2The excavation of foundation pit should adopt the way of comprehensive layering excavation or step layering excavation; The layer thickness shall not be greater than 4m, the slope of the temporary slope in the excavation process should not be greater than1:1.5.

3, mechanical excavation,Above the bottom200mm～300mmThe earthwork within the scope shall be excavated by manual bottom repair, and the excavation slope of the foundation pit excavated by slope excavation shall be excavated by manual slope repair, and overexcavation is strictly prohibited. When the foundation pit is excavated to the elevation of the bottom of the pit, the cushion construction should be carried out in time, and the cushion should be poured to the edge of the retaining wall of the foundation pit or the foot of the foundation pit excavated by the slope.

4The local deep pit adjacent to the foundation pit should be excavated after the completion of a large area of bedding.

5Mechanical excavation should avoid adverse effects on the project pile, and the excavation machinery should not walk directly on the top of the project pile; Earthmoving machinery is strictly prohibited from colliding with engineering piles, parapet walls, supports, columns and column piles, dewatering well pipes, monitoring points, etc., and their surrounding areas 200mm～300mmThe earth within the scope shall be manually excavated.

6, engineering piles should be excavated with earthwork excavation layer above the design elevation part; The treatment of pile top should be carried out after the pouring of cushion.

In the process of foundation pit excavation, if pile foundation, foundation pit support, earthwork excavation, blasting and other construction operations are carried out in adjacent projects around the foundation pit, the construction sequence and method should be reasonably determined according to the actual situation, and reliable technical measures should be taken when necessary.

The construction sequence and method of foundation pit excavation should be adjusted timely according to the monitoring data of foundation pit supporting system and surrounding environment.

The quality acceptance of foundation pit excavation should comply with the current national standard "Code for Quality Acceptance of Building Foundation Engineering"GB50202 The relevant requirements of.

Shanghai Qiangqiang Foundation Engineering Co., LTD. 's business covers foundation pit engineering, pile foundation engineering, land and waterFoundation treatment, slope treatment and other engineering fields. Around" Excellent technology, reliable process", construction fast "technical requirements,Is to provide customers with land, water foundation engineering technical consultation, construction services and other comprehensive solutions of the entity enterprise.Contact Number: 400-100-2850