(1) Settlement observation reference point

(2) Displacement observation reference point

1) Timing to start observation: Start observation after the foundation is completed and the basement is completed.

2) Observation cycle requirements

1) During the foundation pit precipitation and foundation pit excavation process, observe once a day.

2) 10 days after the bottom slab concrete pouring is completed, observation can be made every 2 to 3 days.

3) After the basement roof is completed and the water level is restored, observation can be stopped.

① Arrange in the middle part of the periphery of the foundation pit, at the sunny corner, and near the protected object;

②The horizontal spacing between monitoring points should not be greater than 20m, and the number of monitoring points on each side should not be less than 3.

① Arrange in the middle part of the retaining wall, at the sunny corner, or in a representative part;

②The horizontal spacing between monitoring points is 20~60m, and should not be less than 1 on each side.

1) Abnormal changes in deformation amount or deformation rate;

2) The deformation amount or deformation rate reaches or exceeds the warning value;

3) Collapse, landslides, etc. occur in the surrounding areas or on the excavation surface;

4) Abnormalities occur in the building itself, surrounding buildings and the ground surface;

5) Other abnormal situations caused by natural disasters such as earthquakes, heavy rains, freezing and thawing.

Safety plans must be implemented immediately, and the frequency of observations or the content of observations must be increased at the same time.

1) Soil foundation pit;

2) Extremely soft rock foundation pits, broken soft rock foundation pits, and extremely broken rock foundation pits;

3) The upper part is soil, and the lower part is a soil-rock combination foundation pit composed of extremely soft rock, broken soft rock, and extremely broken rock.

Correct errors

Short answer

① Inspection and inspection contents: supporting structure, construction status, surrounding environment, monitoring facilities, and other inspection and inspection contents.

② Inspection inspection methods and tools: Mainly based on visual inspection, which can be supplemented by tools such as hammers, drills, measuring rulers, magnifying glasses, and equipment such as video and photography.

Short answer

①The basis for determining the monitoring scope of foundation pit projects: foundation pit design depth, geological conditions, surrounding environmental conditions, supporting structure types, construction methods, and the scope of influence of precipitation and ground subsidence.

② Monitoring objects: supporting structures; foundation pits and surrounding rock and soil; groundwater; surrounding protected objects (including: surrounding buildings, pipelines, rail transit, railways, important roads), etc.

③Monitoring content of the enclosure structure: At least the horizontal displacement and settlement of the top of the enclosure wall and the settlement of surrounding buildings, roads, etc. should be monitored, and the deep horizontal displacement of the enclosure wall or soil, internal force of the supporting structure, earth pressure, etc. should be monitored as needed. Pore ​​water pressure, etc. are monitored.

④ When the foundation pit monitoring reaches the deformation warning value, quicksand, piping, uplift, and subsidence occur in the foundation pit, or large deformation occurs in the foundation pit support structure and surrounding environment, an early warning should be issued immediately.

⑤ Deformation monitoring early warning values ​​include: cumulative change early warning values ​​and change rate early warning values ​​of monitoring items.

1) Situations that require monitoring

2) Monitoring items: deformation monitoring, strain monitoring, foundation settlement monitoring

1) Situations that require monitoring

2) Monitoring items: deformation monitoring, strain monitoring, wind and wind-induced response monitoring

① At the four corners of the building, every 10 to 15 meters along the exterior wall, or on the plinth or column of every 2 to 3 columns, there should be no less than 3 points on each side of the exterior wall;

②The boundary between different foundations or foundations;

③The boundary between different structures;

④Both sides of deformation joints, seismic joints or serious cracks;

⑤Both sides of the junction between new and old buildings or high and low buildings;

⑥ The symmetrical parts of the foundation axis of tall structures should not be less than 4 points for each structure.

①Monitoring points should be arranged at building corners, load-bearing columns or walls on both sides of deformation joints;

② Monitoring points should be arranged correspondingly along the top and bottom of the main body, and the upper and lower monitoring points should be arranged on the same vertical line.