Method and device for measuring and monitoring groundwater pressure

Abstract

The invention provides an improved method and device for measuring and real-time monitoring the pressure of water in pores of an underground soil layer. The invention is characterized in that the detection can be realized by pressing a water-permeable water pressure sensor which is protected by a solid shell into underground by virtue of pressure, the water pressure sensor is arranged in a hollow cavity of the solid hollow bullet shell, the rear end of the bullet shell cavity is open so as to form a ventilating channel, a water permeating hole which penetrates the shell walls and is communicated with the hollow cavity is arranged on the bullet shell, a water-permeable mud-blocking layer is arranged between the water permeating hole and / or the water pressure sensor, and the rear end of the bullet shell is provided with a splicing type hollow probing rod in a flexible connection mode, thus the detection of the pressure of water in the pores of underground layer can be realized without excavating and drilling. Furthermore, the method is simple, the detection cost is low, the detection is accurate, the detection of the pressure of water in the pores in multiple different height layers above the maximum depth can be realized, and a new detection method for pressure of the water in the underground pores, especially the pores in the undisturbed soil, can be created.

Description

technical field [0001] The present invention is an improvement to the measurement and real-time monitoring method and device of pore water pressure in the underground soil layer, especially relates to a simple method, low cost, measurement and monitoring without excavation or well drilling, and accurate measurement results Underground pore water pressure method and device. Background technique [0002] With the continuous development of the construction field underground, pile foundation projects and deep and large foundation pits continue to appear. It is necessary to control the pressure of underground pore water (hereinafter referred to as groundwater) that affects pile foundation projects and foundation pit excavation, especially the pore water in undisturbed soil. The pressure is well managed. For example, in the preliminary survey and design stage, it is necessary to understand the groundwater pressure in the soil layer. The difference in groundwater pressure directly...

AI Technical Summary

Problems solved by technology

The disadvantage of this method is: on-site drilling, the hole-forming equipment generally uses a drilling rig, which is bulky and troublesome to transport, and the construction of the drilling rig also has high requirements for the on-site plane site conditions and air obstacle conditions. construction in streets and alleys; secondly, the drilling speed of drilling rigs is slow, and holes are prone to collapse, and water leakage and other accidents are likely to occur if the water insulation is not done well, resulting in waste holes; and secondly, the measurement is mainly done manually after the drilling machine is drilled on site. To measure groundwater pressure, if the water isolation measures are not done well, the groundwater in the upper layer will leak, resulting in inaccurate measured groundwater pressure data; and manual measurement cannot obtain the continuous change of groundwater pressure, and cannot grasp the change of water pressure in real time. Data In addition, the water level observation wells are set at the construction site, and the wellheads cannot be blocked. The observation holes are easily damaged by construction, and the site protection is difficult. After the observation holes are used, they need to be filled with clay or Sealing and backfilling with concrete and other materials is not only cumbersome and costly, but also pollutes groundwater to a certain extent; in addition, a water level observation well can only measure water pressure at one depth, and it is impossible to measure groundwater pressure at different depths at the same time in one well , if it is necessary to measure the groundwater pressure of several layers of soil, it is necessary to drill several observation wells

The stress probe is completely closed as a whole and is completely isolated from the soil layer and the atmosphere, so it can only be used for horizontal stress testing of saturated fine-grained soil, but not for pore water pressure testing in undisturbed soil

[0008] Therefore, in the prior art, the pore water pressure test in the underground soil layer, especially the undisturbed soil, still stays in the excavation and drilling mode, and a well can only measure the pore water pressure at the maximum depth (hole bottom position); adopt The pressure sensor needs to be pre-placed and buried in the soil layer to be tested. It is mostly used for groundwater pressure testing in backfill soil, and cannot be used for pore water pressure measurement after entering the formation (undisturbed soil). The above shortcomings still have room for improvement

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