Auxiliary installation method of inclinometer for monitoring deep horizontal displacement of deep foundation pit

Abstract

The invention discloses an auxiliary installation method of an inclinometer for monitoring deep horizontal displacement of a deep foundation pit. A PVC sleeve (1), a drilling machine (2) provided witha mud pump (2-1), a rubber pipe (3) and the inclinometer (4) are included, the drilling machine (2) drills a hole in a soil slope in advance, the mud pump (2-1) is started in the drilling process, bentonite mud which is stirred in advance and has a specific concentration is pumped through the rubber pipe (3), and the mud protects the wall of the drilled hole through a hollow drill rod; when drilling is carried out to the designed elevation of the bottom of the hole, the PVC sleeve (1) is placed in the drilled hole section by section; the rubber pipe (3) at an inlet of the mud pump is insertedinto the bottom of the PVC sleeve (1) in the drilled hole, and the mud pump (2-1) is started to pump out the mud in the drilled hole; then the rubber pipe at the inlet of the mud pump is pulled out,and the inclinometer (4) is placed in the PVC sleeve (1) section by section; and then the PVC sleeve (1) is pulled out section by section, and finally fine sand is backfilled into the drilled hole forhole shrinkage.

Description

technical field [0001] The invention belongs to the technical field of foundation pit monitoring, and in particular relates to an auxiliary installation method for an inclinometer tube for deep horizontal displacement monitoring of deep foundation pits. Background technique [0002] The deep horizontal displacement monitoring of the foundation pit is a reliable basis for the stability analysis of the slope (deep foundation pit), and the accuracy of the measurement results is the guarantee for checking the construction quality and controlling the construction progress. [0003] The monitoring of the deep horizontal displacement of the foundation pit requires the installation of the inclinometer tube. According to the different support structures (soil nail wall, steel sheet pile, cast-in-place pile, ground connection wall) of the slope (deep foundation pit), there are also different installation methods for the inclinometer tube. Differences, such as: in the cast-in-situ pile...

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Problems solved by technology

[0003] The monitoring of the deep horizontal displacement of the foundation pit requires the installation of the inclinometer tube. According to the different support structures (soil nail wall, steel sheet pile, cast-in-place pile, ground connection wall) of the slope (deep foundation pit), there are also different installation methods for the inclinometer tube. Differences, such as: in the cast-in-situ pile support, the inclinometer pipe should be bound on the steel cage, and then lowered into the borehole as a whole; For soil nailing wall support or grading excavation areas, it is usually used to drill holes near the slope to bury the inclinometer pipe, and then backfill the gap between the inclinometer pipe and the borehole. It has been widely used by relevant technical personnel, but with the increase in practical application, this method has also exposed many problems, such as: 1. Difficulty in lowering the inclinometer pipe, and the bottom of the pipe cannot reach the design depth, resulting in measurement results that do not meet the specification requirements; After the assembly of the inclinometer tube is completed, the overall airtightness is good, but there is a high water level in the borehole due to the influence of the grouting retaining wall and the groundwater level, which makes it difficult to lower the inclinometer tube to the bottom of the hole due to the large buoyancy when it is lowered. And there is a hidden danger of floating after it is lowered; 2. The quality of the borehole shrinkage is poor, resulting in poor accuracy of the measurement results, and the measurement data cannot be applied; due to the presence of a certain concentration of mud in the borehole and the impact of water pressure, the drill The hole backfill cannot sink to the bottom of the hole, and with the decrease of the water level in the hole and the influence of precipitation infiltration, the backfill sinks, and the borehole appears "hollow", so the measurement data cannot be used due to the shaking of the inclinometer pipe during measurement

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