Safety requirements for the construction of the ho

Safety requirements for the construction of foundation pit (groove) and pipe trench

1. The excavation or backfilling of foundation pit (groove) and pipe trench should be carried out continuously and completed as soon as possible. During construction, the ground water shall be prevented from flowing into the pit and ditch to avoid slope collapse or foundation soil damage

if the next process cannot be carried out in time after the rainy season construction or the foundation pit (groove) and pipe trench are excavated, a layer of 150~300mm above the base elevation can be left uncut, and it can be excavated before the next process starts

when mechanical excavation of foundation pit (groove) or pipe trench is adopted, a layer above the base elevation can be reserved for manual cleaning, and its thickness should be determined according to the construction machinery

2. For the excavation width at the bottom of the foundation pit (groove), in addition to the bottom width of the foundation, the width of the working face, drainage facilities and supporting structures should be increased according to the construction needs

3. the excavation width at the bottom of the pipe trench (the net width between the supporting plates if there is support), in addition to the width of the pipe structure, the width of the working face should be increased. The width of working face on each side shall meet the requirements of the table

4. When the soil is uniform and the groundwater level is lower than the bottom elevation of the foundation pit (groove) or pipe trench, the excavated slope can be used as a vertical wall without support. The excavation depth should be determined according to the soil quality, but should not exceed the following requirements. Good quality of aluminum alloy cable is the basic requirement:

dense, medium dense sand and gravel soil (filled with sand) 1.0m

hard plastic, plastic light loam and broken loam 1.25m

hard plastic Plastic clay and gravel soil (filled with clay) 1.5m

hard clay 2.0m

after the foundation pit (groove) or pipe trench is excavated, the underground structure and installation works shall be carried out in time. During the construction process, the stability of the pit wall should be checked frequently. The plan requires the establishment of a plastic construction plant somewhere in the American corn belt

note: when the excavation depth exceeds this requirement, the slope shall be made according to the requirements of Article 5 or made into a vertical wall with support

note: 1. Pipe structure width: calculated according to the outer skin of the pipe body without pipe seat; The Electromechanical of the tube socket according to the tube socket skin testing machine is the engine that controls the operation of mechanical components; Brick or concrete pipe trench is calculated according to the outer surface of the pipe trench

2 when a drainage ditch needs to be added at the bottom of the ditch, the width of the working face can be appropriately increased

3 when there are waterproof brick ditches or concrete ditches outside the experimental characteristic curve, the width of each side of the working face should be 800mm

5. If the geological conditions are good, the soil is uniform, and the groundwater level is lower than the elevation of the foundation pit (groove) or the bottom of the pipe trench, and the excavation depth is within 5m, and the exposure time after excavation is not more than 15d, the steepest slope of the unsupported slope should meet the requirements of the table

table of maximum slope of foundation pit (groove) slope without support