As well as pipeline reinforcement, lead to change, relocation program.
2 construction personnel to obtain technical clarification and safety tests. The location of the clear pit geological conditions, groundwater conditions, Ming
To ensure the location of underground structures and measures to be protected.
3 explicit support (support) type, supporting materials, supporting steps, support requirements; clear excavation order; clear
Base elevation and quality requirements.
4 work should be prepared before the excavation, embankment (or temporary soil) of the balanced deployment, reasonable arrangement of earthwork transportation routes and abandoned
Soil site, excavation should be continuous rapid construction, should not be interrupted.
5 urban bridge construction, the excavation of the foundation pit backfill construction process should be in accordance with the "earthwork and foundation construction technical procedures"
Q/BMG 102 requirements.
6 large foundation pit (danger of large foundation pit) should be based on the risk of a larger part of the project safety management measures
(building a quality  87 text) to organize experts to demonstrate special programs.
Measurement line * (earth excavation without support, supporting). Base construction acceptance. Bridge culvert structure inspection.
Close, foundation pit backfill.
Determination of the bridge line, using control network encryption pier location, the height measuring to the bridge location.
To ensure the accuracy of the relative error of the distance measurement in the middle of the bridge.
Location of pier line, setting out the cross positioning line. Put the foundation pit and the axis line, measured in the ground pit
Excavation of foundation pit
1 excavation of foundation pit should be based on the soil and the site condition, to reasonably determine the excavation sequence, and then divided into
The average level of the excavation.
The excavation should be symmetrical excavation or circular excavation, stratified excavation, first support after excavation, not by
2 when the anti shovel excavator is used to dig the foundation pit, the construction method has the following two kinds of:
1) groove excavation pit (groove): Excavator from end to back running method of dump truck with excavation.
The soil on both sides of the excavator's shipment.
2) lateral groove excavation: Excavator side along the side of the pit (groove), the other side is provided with a dump truck
3 dimensions should meet the requirements of the construction of foundation pit. When the pit soil basal water seepage, drainage pit size should be based on to
Requirements (including the drainage ditch, water collection and drainage pipe network, etc.) and the foundation of the design of the foundation pit size required.
The base should be larger than the base plane size of 3 a 0.5 0m. when the template is not set, the size of the base can be opened at the end of
4 pit wall slope should be according to the geological conditions, the depth of foundation pit, construction methods and so on.
The foundation pit depth is less than 5m, the construction period is relatively short, the bottom of foundation pit is above the ground water level, the soil moisture is close to
When the structure of the soil layer is uniform, the slope of the pit wall can be determined according to the table 5.3.3.