Foundation pit top horizontal displacement monitoring method

Abstract

The invention discloses a foundation pit top horizontal displacement monitoring method which comprises a longitudinal foundation pit edge monitoring point monitoring link and a transverse foundation pit edge monitoring point monitoring link. The longitudinal foundation pit edge monitoring point monitoring link includes the following steps that 1, firstly a foundation pit corner portion point B1 is selected to serve as a static benchmark point, monitoring points are set on two longitudinal edges of a foundation pit respectively, the monitoring points before excavation are Bi and C i+1 (i=1, 2,......n) respectively, the corresponding monitoring points after excavation become B' i and C' i+1 respectively; 2, before excavation is conducted on the foundation pit, the distance between B i and B i+1 is monitored to be B i * B i+1, and the distance between the B i+1 and the C i+1 is monitored to be B i+1* C i+1; 3, after excavation is conducted on the foundation pit, the distance between the B' i and the C' i+1 is monitored to be B' i *C' i+1, and the distance between the B' i+1 and C' i+1 is monitored to be B' i+1 * C' i+1; 4, the horizontal displacement of the monitoring point Bi and the horizontal displacement of the monitoring point C i are obtained according to the value of the B i * B i+1, the B i+1* C i+1, the B' i *C' i+1 and the B' i+1 * C' i+1. The horizontal displacement monitoring method is high in measuring accuracy and low in requirement for professional skills of monitoring personnel, and monitoring can be finished conveniently just by operation of a single person.

Description

technical field [0001] The invention relates to a foundation pit monitoring method, in particular to a method for conveniently monitoring the horizontal displacement of the top of the foundation pit. Background technique [0002] During the construction of the foundation pit, the horizontal displacement of the top of the enclosure structure is the main evaluation index of the safety of the foundation pit, so it is the main item that must be monitored during the construction of the foundation pit. Existing methods for monitoring the horizontal displacement of the top of the foundation pit enclosure mainly include the axis method, the small angle method, and the coordinate change method of the total station. The station instrument measures the included angle and distance at the same time, and uses the conversion formula to calculate the displacement value. The above monitoring methods have certain disadvantages. The axis method and the small angle method have higher requireme...

AI Technical Summary

Problems solved by technology

The above monitoring methods have certain disadvantages. The axis method and the small angle method have higher requirements on the site. The base point of the monitoring work should be selected not far from the foundation pit and a point that does not move during the excavation process of the foundation pit. The theodolite reads the steel ruler reading accuracy is low, especially when the distance is long; the measurement accuracy of the total station coordinate change method is not high, but the measurement process is cumbersome, the measurement cost is high, and the professional skills of the monitoring personnel are high. Both methods require two or more people to monitor

[0003] A method for measuring the displacement of foundation pits has been mentioned in some patent documents, but this method needs to set a reference point for each pair of horizontal displacement monitoring points, which is easily limited by site conditions and difficult to implement; especially for short foundation pits with long strips Due to the distance between the two sides, it is very difficult to monitor with this method, so it is urgent to find a simple and convenient method for measuring the horizontal displacement of the foundation pit, which has extremely practical significance

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