Slurry shield model test mud cake thickness real-time measurement device and measurement method

Abstract

The invention provides a slurry shield model test mud cake thickness real-time measurement device which structurally comprises an air compressor, a valve A, a pressure regulating valve, a valve B, a sludge barrel, sludge, a valve C, a glass barrel, a valve D, a measuring cylinder, filtrate, an electronic balance, a computer, hoses and a valve E, wherein the air compressor is connected with the sludge barrel through the hoses, the valve A, the pressure regulating valve and the valve B, the sludge barrel is connected with the glass barrel through the hoses and the valve C, the glass barrel is connected with the measuring cylinder containing the filtrate through the hoses and the valve D, the measuring cylinder is placed on the electronic balance, the electronic balance is connected with the computer through a serial data cable, the valve E is connected with the glass barrel, and the sludge is placed in the sludge barrel. A real-time measurement method includes the steps: (1) preparing the sludge, a stratum layer and a filter layer; (2) measuring the thickness of a mud cake in real time. The device has the advantage that the thickness of the mud cake can be measured by probe pressure in real time conveniently and accurately.

Description

technical field [0001] The invention relates to a real-time measuring device and a measuring method for mud skin thickness in a mud-water shield model test, which belongs to the field of geotechnical engineering and tunnel engineering, and relates to a measuring method for a mud film formation process for ensuring the stability of a mud-water shield excavation surface. Background technique [0002] Slurry shields are widely used in tunnel projects such as subways, railways, highways, municipalities, and hydropower. Under complex stratum conditions, shield machine excavation faces huge engineering risks, and it is easy to cause collapse of the excavation surface, surface subsidence and uplift. Therefore, it is necessary to ensure The stability of the excavation surface, the calculation and formation of an effective mud film on the excavation surface is the key to ensure the stability of the excavation surface, determine the growth law of the thickness of the mud skin under dif...

AI Technical Summary

Problems solved by technology

[0003] However, the traditional mud-water shield model test can only roughly estimate the thickness of the mud skin with a scale after the pressure is relieved, and the mud skin will be deformed and destroyed by the disturbance after the pressure is relieved, causing the thickness of the mud skin to be different from that of the mud skin. There are differences in the actual value, and only the thickness of the mud skin at the moment after pressure relief can be obtained

In addition, it is difficult for conventional thickness testing instruments to accurately determine the boundary of the mud skin, and only an estimated value can be obtained. For thin mud skins, the measurement error may be greater than the thickness of the mud skin itself, which is difficult to apply to the judgment of mud skin properties and mud proportioning schemes Therefore, it is necessary to study the relationship between the thickness of the mud skin and the pressure drop of the mud skin, so as to understand the formation time of the mud film more accurately and intuitively and to measure the thickness of the mud skin in real time, making up for the shortcomings of the traditional method

[0004] The traditional measurement of mud skin thickness after pressure relief has the following disadvantages: ①The formation and mud skin will be deformed after pressure relief, and the mud skin and the formation contact may be disengaged or cracked, and the measurement of mud skin thickness is inaccurate; ②Unloading Taking soil after compaction is easy to disturb the formation and the mud skin, causing the mud skin to deform, the measured value is quite different from the real value, and the traditional ruler to measure the thickness of the mud skin is not accurate enough, and there are human reading errors; ③ extract the mud skin after pressure relief The mud on the surface will also be disturbed during the extraction process, resulting in large differences in the values ​​measured at different locations, making it difficult to accurately determine the real mud thickness; It is also difficult to obtain the key data for judging the quality of the mud skin by obtaining the growth law of the mud skin thickness during the test

[0005] The traditional method of reading the thickness of the mud skin directly from the inner wall of the model glass cylinder has the following disadvantages: ①The color difference between the mud skin and the mud is small, and the interface between the two is difficult to determine; ②The glass cylinder avoids capillary action, and the mud thickness read from the wall The skin thickness may be slightly greater than the real mud skin thickness, but this added value is affected by many factors and it is difficult to determine; ③ The mud skin thickness may be different at different positions inside the mud skin, and this difference in mud skin thickness cannot be obtained from the model glass tube. The thickness of the mud skin on the inner wall is obtained; ④The thickness of the mud skin is difficult to read accurately and cannot be measured in real time

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