Slurry penetration film-forming test equipment for slurry shield of composite stratum
The soil sample layer was simulated through the composite formation mud water shield mud permeation membrane forming test equipment and conducted mud permeation tests, which solved the problem that mud indicators could not be controlled in advance in the existing technology, and achieved the effect of adjusting mud indicators in advance according to the formation changes in the excavation construction to ensure construction stability.
Patent Information
- Application Number
- CN202420707950.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-08
- Publication Date
- 2025-03-11
- Estimated Expiration
- 2034-04-08
AI Technical Summary
The existing technology cannot control mud indicators in advance, resulting in insufficient stability during the construction of mud water balance shield structures, especially in complex and mud strata, which may lead to problems such as palm surface collapse and mud water storage storage and stagnation.
It provides a mud-water shield mud permeation membrane formation test equipment for composite formation, including permeation cylinder, pneumatic pressure device, water supply device and leachate detection device. It can simulate the soil sample layer of various composite formations, conduct mud-water shield mud permeation membrane formation test, intuitively observe mud permeation status and adjust mud index.
By controlling the mud indicators in advance, it is possible to ensure that the mud film characteristics meet the stability requirements according to the actual formation changes during excavation construction, and improve the stability and efficiency of shield tunneling construction.
Smart Images
Figure CN222599454U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical fields of mud-water shield construction, and in particular to a composite stratum mud-water shield mud penetration film-forming test device. Background Art
[0002] Due to its high efficiency, safety and reliability, shield tunnel construction technology has been rapidly developed in various engineering practices such as urban subways, municipal roads, and water diversion. In particular, slurry shields are widely used in the construction of underwater tunnels on the seabed or across rivers. The slurry shield balances the water and soil pressure of the excavation surface strata by adjusting the mud pressure in the pressure chamber. Since the mud pressure is greater than the pore water pressure of the strata, the fine particles in the mud will penetrate into the strata under the action of the pressure difference to form an impermeable mud film, thereby stabilizing the strata. Therefore, the permeability and film-forming properties of the mud on the strata are directly related to the stability of the slurry shield excavation.
[0003] The existing method is to control the mud indicators (including viscosity, specific gravity, pH value, etc.) during the excavation construction to make the mud film characteristics meet the stability of the slurry shield excavation. However, this method cannot control the mud indicators in advance. It is necessary to observe the stability of the excavation and adjust the mud indicators in turn when instability occurs. It is not timely enough and requires continuous attempts, which affects the construction progress and quality. Moreover, my country has a vast territory and will encounter various complex strata during shield construction. When the geology suddenly changes during the excavation process, the existing mud indicators (viscosity, specific gravity, pH value, etc.) do not meet the excavation requirements of the sudden change strata. Face collapse, mud and water storage storage and drainage delays may occur, which restricts the efficiency of shield excavation construction. Utility Model Content
[0004] In order to solve the above problems, the utility model provides a composite stratum mud-water shield mud penetration film-forming test equipment, which can carry out mud-water shield mud penetration film-forming tests on various soil sample layers, so as to control the mud indicators in advance according to the actual stratum changes during excavation construction and ensure the stability of excavation construction.
[0005] The utility model is realized by the following scheme, a composite stratum mud water shield mud penetration film forming test equipment, comprising:
[0006] A vertically arranged permeable cylinder whose interior can be seen through, wherein the interior of the permeable cylinder is provided with a filter layer, a soil sample layer prepared by using actual stratum soil, and a mud cavity for grouting in order from bottom to top, the top of the permeable cylinder is detachably and sealedly connected with an upper cover, the upper cover is provided with an air inlet hole that can be connected to the interior of the permeable cylinder, the bottom of the permeable cylinder is sealedly connected with a lower cover, the lower cover is provided with a water inlet hole and a liquid outlet hole that can be connected to the interior of the permeable cylinder, and the air inlet hole, the water inlet hole, and the liquid outlet hole are all provided with valves for controlling the opening and closing of the holes;
[0007] A pneumatic device for delivering compressed gas to the inside of the permeation tube to assist in completing the mud permeation test, wherein the pneumatic device is connected to the air inlet hole through an air inlet pipe;
[0008] A water supply device for injecting water into the infiltration cylinder to saturate the soil sample layer and assist in completing the constant water head test, wherein the water supply device is connected to the water inlet hole through a water inlet pipe;
[0009] A leachate detection device is used for collecting the leachate flowing out from the liquid outlet and calculating the permeation flow rate and permeability coefficient based on the flowing leachate.
[0010] A further improvement of the composite stratum mud-water shield mud permeation film-forming test equipment of the utility model is that a scale mark for representing the height is arranged on the permeation cylinder along the height direction.
[0011] The utility model is a further improvement of the composite stratum mud-water shield mud permeation film forming test equipment in that: a plurality of piezometers are arranged at intervals along the height direction on the permeation cylinder to respectively monitor the pressures at different height positions of the soil sample layer.
[0012] The utility model is a further improvement of the composite stratum mud-water shield mud permeability film-forming test equipment in that: the topmost piezometer is 1 to 2 cm lower than the initial elevation of the top surface of the soil sample layer.
[0013] A further improvement of the composite stratum mud-water shield mud permeability film-forming test equipment of the utility model is that the air pressure device includes an air compressor and a pressure stabilizing device connected to the air compressor to adjust the output air pressure of the air compressor, and all the pore pressure gauges are connected to the pressure stabilizing device.
[0014] A further improvement of the composite stratum mud-water shield mud penetration film-forming test equipment of the utility model is that the water supply device is a water supply funnel, the water inlet pipe is connected to the bottom of the water supply funnel, and the bottom elevation of the water supply funnel is higher than the initial elevation of the top surface of the soil sample layer.
[0015] A further improvement of the composite stratum mud-water shield mud permeability film-forming test equipment of the utility model is that the filter layer includes a geotextile laid on the lower cover, and a quartz sand layer laid on the geotextile, and the thickness of the quartz sand layer and the quartz sand particle size meet the requirements that the permeability of the filter layer is much higher than the permeability of the soil sample layer.
[0016] The utility model can simulate soil sample layers of various composite strata, and can pre-perform mud-water shield mud penetration film-forming tests on soil sample layers. The penetration of mud under different soil sample layers can be intuitively observed, and the quality of the mud film formed can be directly obtained. The mud index is adjusted based on the test results, and then the best mud index suitable for different soil sample layers is obtained, so that the mud index can be controlled in advance according to the actual stratum changes during excavation construction to ensure the stability of excavation construction. In addition, the utility model makes it more convenient to prepare the soil sample layer and inject mud through the detachable setting of the upper end cover, and the soil sample layer can be saturated by the height matching of the water supply funnel and the penetration tube. The pressure at different height positions of the soil sample layer can be monitored separately through the setting of several piezometers, so that the test results are more accurate, and the entire equipment is simple to manufacture and easy to operate. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 The schematic diagram of the vertical structure of the penetration tube in the test equipment of the utility model is shown.
[0018] Figure 2 The utility model test equipment schematic diagram is shown. DETAILED DESCRIPTION
[0019] In order to solve the problem that the traditional slurry shield cannot control the mud index in advance for different strata during excavation construction, so that the characteristics of the formed mud film meet the stability of excavation construction. The utility model provides a composite stratum slurry shield mud penetration film test equipment, which can perform slurry shield mud penetration film test on various soil sample layers, so as to control the mud index in advance according to the actual stratum changes during excavation construction, and ensure the stability of excavation construction. The composite stratum slurry shield mud penetration film test equipment is further described below with specific embodiments combined with the accompanying drawings.
[0020] See also Figure 1 and Figure 2 As shown, a composite stratum mud-water shield slurry permeation film forming test equipment comprises:
[0021] A vertically arranged infiltration cylinder 1 through which the interior can be seen is provided, wherein the interior of the infiltration cylinder 1 is provided with a filter layer 11, a soil sample layer 12 prepared by using actual stratum soil, and a mud cavity 13 for grouting in sequence from bottom to top; the top of the infiltration cylinder 1 is detachably and hermetically connected with an upper cover 2, on which an air inlet 21 which can be connected to the interior of the infiltration cylinder 1 is provided; the bottom of the infiltration cylinder 1 is sealedly connected with a lower cover 3, on which a water inlet 31 and a liquid outlet 32 which can be connected to the interior of the infiltration cylinder 1 are provided; and valves for controlling the opening and closing of the holes are provided at the air inlet 21, the water inlet 31 and the liquid outlet 32. Specifically, the infiltration tube 1 is made of cylindrical organic glass, with an inner diameter of 30 cm and a height of 150 cm. The filter layer 11 includes a geotextile laid on the lower cover 3 and a quartz sand layer laid on the geotextile. The arrangement of the geotextile prevents the water inlet 31 and the liquid outlet 32 at the bottom of the infiltration tube 1 from being blocked by quartz sand particles. In order to separate the filter layer 11 and the soil sample layer 12, another layer of geotextile can be laid between the quartz sand layer and the soil sample layer 12. The soil sample layer 12 has a thickness of 40 cm to 45 cm and is prepared according to the actual stratum conditions. The soil body of the actual stratum can be used for preparation, and the density of the soil body at different heights is ensured to be the same as that of the actual stratum during preparation. The density can be verified according to the mass and volume of the soil body. In order to ensure that the permeability of the filter layer 22 is much higher than that of the soil sample layer 12, it is preferred to use coarse-grained quartz sand to prepare the quartz sand layer, and the thickness of the quartz sand layer is about 15 cm. The upper cover 2 is a flange, which is detachably connected to the top of the permeation cylinder 1. In order to ensure that the mud chamber 13 is a closed chamber when the upper cover 2 is connected to the permeation cylinder 1, a sealing ring is preferably provided between the upper cover 2 and the permeation cylinder 1. It should be noted that valves are provided at the above-mentioned air inlet 21, water inlet 31 and liquid outlet 32, and the corresponding holes are opened and closed by controlling the corresponding valves.
[0022] A pneumatic device for delivering compressed gas to the inside of the permeable cylinder 1 to assist in completing the mud permeability test, the pneumatic device is connected to the air inlet 21 through an air inlet pipe. Specifically, the pneumatic device includes an air compressor and a pressure stabilizing device connected to the air compressor to adjust the output air pressure of the air compressor. The pressure stabilizing device can be connected to a computer, and the pressure stabilizing device is controlled through the computer's operating interface to adjust the output air pressure of the air compressor. When conducting a mud permeability test, the air compressor is used to deliver compressed gas to the inside of the permeable cylinder 1. The compressed gas will act on the mud surface, thereby converting it into the pressure of mud penetration. In addition, since the ability of the soil at different heights of the composite formation to withstand pressure is different, in order to simulate the composite formation, in this embodiment, a plurality of piezometers 4 are arranged at intervals along the height direction on the permeable cylinder 1 to respectively monitor the pressure at different heights of the soil sample layer 12, so that when preparing the soil sample layer 12, the monitoring of each piezometer 4 ensures that the prepared soil sample layer 12 can more accurately restore the actual composite formation. In addition, after the mud is introduced and pressurized, the hydraulic and air pressures can also be measured by each piezometer 4. The range of each piezometer 4 is 0Mpa~1Mpa, and the accuracy is 0.25kPa. All piezometers 4 are connected to the pressure stabilizing device and displayed through the operation interface. Preferably, in order to ensure the measurement accuracy of the piezometer, a geotextile is provided in front of the opening of each piezometer to prevent soil particles from entering its internal cavity. It should be noted that each piezometer 4 is arranged corresponding to the height range of the soil sample layer 12, but in order to prevent the soil sample layer 12 from being compressed downward due to the high pressure, causing the piezometer reading to change from the soil sample layer pore pressure to the mud pressure, this embodiment chooses to set the topmost piezometer at a height slightly lower than the initial elevation of the top surface of the soil sample layer 12 (such as Figure 1 The position of the pore pressure gauges is preferably 1 cm to 2 cm lower than the initial elevation of the top surface of the soil sample layer 12, and all the pore pressure gauges are evenly spaced.
[0023] A water supply device is used to inject water into the infiltration cylinder 1 to saturate the soil sample layer 12 and assist in completing the constant water head test. The water supply device is connected to the water inlet hole 31 through a water inlet pipe. Specifically, the water supply device includes a water supply funnel and a water supply pump for continuously supplying water to the water supply funnel. The water supply funnel is vertically suspended at a fixed height (the fixed height should ensure that the bottom elevation of the water supply funnel is higher than the initial elevation H2 of the top surface of the soil sample layer 12, so that the water in the water supply funnel can be automatically supplied to the infiltration cylinder 1 under the action of its own weight during water supply), and the water inlet pipe is connected to the bottom of the water supply funnel.
[0024] A leachate detection device for collecting leachate (including water and / or mud) flowing out of the liquid outlet 32 and calculating the permeation flow rate and permeability coefficient based on the outflowing leachate. Specifically, the leachate detection device includes a liquid collection container and an electronic scale. The liquid collection container is connected to the liquid outlet 32 through a liquid collection pipe to collect the leachate. The electronic scale is used to weigh the mass of the collected leachate, which can be converted into the volume of the leachate through mass-volume conversion. Based on the principle of permeation, the volume of the leachate can be converted into the permeation flow rate per unit area, in units of m 3 / m 2 .
[0025] A composite stratum mud-water shield slurry permeability film forming test method, using the composite stratum mud-water shield slurry permeability film forming test equipment as described above to conduct the test, in conjunction with Figure 1 and Figure 2 As shown, the test method comprises the steps of:
[0026] Step 1, preliminary installation of the main body of the test equipment. Install the piezometers 4 on the side wall of the permeation cylinder 1, connect the line end interface of each piezometer 4 to the voltage stabilizer, connect the computer to the port of the voltage stabilizer, and then reset the readings of each piezometer. Finally, close the valves of the air inlet 21, the water inlet 31 and the liquid outlet 32.
[0027] Step 2, prepare the filter layer 11 and the soil sample layer 12. Open the upper cover 2 of the infiltration cylinder 1, and lay a layer of geotextile in the infiltration cylinder 1 to prevent the water inlet 31 and the liquid outlet 32 at the bottom of the infiltration cylinder 1 from being blocked by soil particles. Then, lay coarse quartz sand particles with a thickness of about 15 cm on the geotextile to form a quartz sand layer, and ensure that the permeability of the quartz sand layer is much higher than that of the soil sample layer 12. A layer of geotextile is laid on the quartz sand layer to isolate the soil sample layer 12 and the filter layer 11. Next, prepare the soil sample layer 12, and set the thickness of the soil sample layer 12 to 40cm to 45cm. Use the "rain fall method" to prepare the sample, control the dry soil fall distance to be constant, and fill it in 9 times. After each filling, check the height of the soil sample layer and verify its density according to the mass and volume of the soil sample to ensure that the dry density of the soil sample layer is stable at 1.53g / cm 3 (This density value depends on the actual formation characteristics). In order to prevent the soil sample layer 12 from being compressed under high pressure and the top surface elevation being lower than the topmost piezometer, thereby causing the piezometer reading to change from the soil sample layer pore pressure to the mud pressure, when preparing the soil sample layer 12, the initial elevation of the soil sample layer 12 should be controlled to be 1 cm to 2 cm higher than the topmost piezometer.
[0028] Step 3, soil sample layer saturation and transmission coefficient measurement. After the soil sample layer 12 is prepared, the soil sample layer 12 is saturated. First, open the valves at the water inlet 31 and the liquid outlet 32, and use the water supply device to inject water into the infiltration tube 1 from the water inlet 31 to saturate the soil sample layer 12. In order to ensure that the bubbles in the soil sample layer 12 are discharged smoothly and reach a fully saturated state, the water in the water supply funnel is controlled to slowly pass from the bottom of the infiltration tube 1 to the bottom of the soil sample layer 12 under the action of its own weight, so as to achieve saturation of the soil sample layer 12 from bottom to top. This process lasts about 3h to 4h. Then a constant water head test is carried out to verify the permeability of the soil sample layer 12. The test shows that the permeability coefficient of the soil sample layer 12 is 2.5×10 -3 ~3.5×10 -3 cm / s, when the actual formation permeability is 10 -3 ~10 -2 The range of cm / s is medium permeable stratum.
[0029] Step 4, introduce mud. After the constant head test is completed, close the valves at the water inlet 31 and the outlet 32, scoop out the water in the infiltration tube 1 with a spoon, and gently scrape the surface of the soil sample layer 12 with a glass slide, and then introduce the mud. In order to avoid disturbing the soil sample layer 12 when introducing the mud, first use an ear bulb to slowly inject the mud along the inner wall of the infiltration tube 1. When the mud level rises by 3c~5cm, use the glass rod drainage method to make the mud flow into the infiltration tube 1 along the glass rod. At this time, the rate of introducing the mud can be slightly increased, and the final mud height is controlled to be about 20cm. Since the infiltration tube 1 is a transparent material, the mud level and the top surface elevation of the soil sample layer 12 (the initial height is Figure 1 The height H1 shown in the figure will change with the introduction and penetration of mud) and the top elevation of the filter layer 11 (the initial height is Figure 1 At the height H1 shown, the height will change with the introduction and penetration of mud) and all situations can be directly observed. Of course, in order to directly obtain the corresponding elevation value, a scale mark 5 representing the height can be set on the permeable cylinder 1, and a scale sticker can be pasted on the permeable cylinder 1. The mud level after the introduction, the top surface height of the soil sample layer 12 and the top surface height of the filter layer 11 should all meet the requirements of the mud penetration test. In addition, after the mud is introduced, the initial pore pressure of each piezometer 4 is read through the operation interface.
[0030] Step 5, conduct a mud penetration test. Connect the upper cover 2 to the permeation tube 1, so that the mud chamber 13 is a sealed chamber, then open the valves at the air inlet 21 and the liquid outlet 32 at the same time, then set the air pressure through the pressure stabilizing device according to the test requirements, and use the air pressure device to deliver compressed gas to the permeation tube 1. During the test, the pore pressure values of each piezometer 4 can be read through the operation interface, so as to realize the monitoring of the pressure change during the whole process, and use the leachate detection device to collect the leachate and calculate the permeate flow rate. Combined with the monitored pore pressure values and the calculated permeate flow rate, it is judged whether the introduced mud meets the requirements. It should be noted that during the test, attention should be paid to observing the morphology of the leachate. If the leachate is turbid, it means that the soil sample layer 12 is punctured and the mud has a large amount of filtration loss. At this time, the test should be stopped.
[0031] Preferably, it also includes step 6, testing the basic properties of the mud film. After the mud permeability test is completed, the valves at the air inlet 21 and the liquid outlet 32 are closed, the upper cover 2 is opened, the remaining mud is scooped out with a spoon, and the floating slurry on the surface of the mud film is sucked out with an ear bulb, the accumulation state of the mud film and the mud permeability range are observed, and then the mud film and part of the stratum are taken out with a circular knife with a diameter of 100 mm, the floating slurry on the surface of the mud film is blown off, the thickness of the mud film is measured with a vernier caliper, and finally the mud film is scraped with a geotechnical knife to measure its moisture content.
[0032] The utility model can simulate soil sample layers of various composite strata, and can pre-perform mud-water shield mud penetration film-forming tests on soil sample layers. The penetration of mud under different soil sample layers can be observed intuitively, and the quality of the mud film formed can be directly obtained. The mud index is adjusted based on the test results, and then the best mud index suitable for different soil sample layers is obtained, so that the mud index can be controlled in advance according to the actual stratum changes during excavation construction to ensure the stability of excavation construction. In addition, the detachable setting of the upper end cover makes it more convenient to prepare the soil sample layer and inject the mud. The height coordination of the water supply funnel and the infiltration cylinder makes it easy to saturate the soil sample layer. The setting of several piezometers can realize the monitoring of the pressure at different heights of the soil sample layer, making the test results more accurate. The entire device is simple to manufacture and easy to operate.
[0033] The utility model is described in detail above in conjunction with the embodiments of the drawings. A person skilled in the art can make various variations of the utility model according to the above description. Therefore, some details in the embodiments should not constitute a limitation of the utility model, and the scope of protection of the utility model shall be defined by the scope of the attached claims.
Claims
1. A composite stratum mud shield slurry permeability film forming test equipment, characterized in that: include: A vertically arranged permeable cylinder through which the interior can be seen, wherein the interior of the permeable cylinder is provided with a filter layer, a soil sample layer prepared by using actual stratum soil, and a mud cavity for grouting in order from bottom to top, the top of the permeable cylinder is detachably and sealedly connected with an upper cover, the upper cover is provided with an air inlet hole that can be connected to the interior of the permeable cylinder, the bottom of the permeable cylinder is sealedly connected with a lower cover, the lower cover is provided with a water inlet hole and a liquid outlet hole that can be connected to the interior of the permeable cylinder, and the air inlet hole, the water inlet hole, and the liquid outlet hole are all provided with valves for controlling the opening and closing of the holes; A pneumatic device for delivering compressed gas to the inside of the permeation tube to assist in completing the mud permeation test, wherein the pneumatic device is connected to the air inlet hole through an air inlet pipe; A water supply device for injecting water into the infiltration cylinder to saturate the soil sample layer and assist in completing the constant water head test, wherein the water supply device is connected to the water inlet hole through a water inlet pipe; A leachate detection device is used for collecting the leachate flowing out from the liquid outlet and calculating the permeation flow rate and permeability coefficient based on the flowing leachate.
2. The composite stratum mud-water shield slurry permeation film forming test equipment according to claim 1, characterized in that: The infiltration cylinder is provided with scale marks for indicating the height along the height direction.
3. The composite stratum mud-water shield slurry permeation film forming test equipment according to claim 1, characterized in that: A plurality of pore pressure gauges are arranged at intervals along the height direction on the permeable cylinder to respectively monitor the pressures at different height positions of the soil sample layer.
4. The composite stratum mud-water shield slurry permeation film forming test equipment according to claim 3, characterized in that: The topmost piezometer is 1 to 2 cm lower than the initial elevation of the top surface of the soil sample layer.
5. The composite stratum mud-water shield slurry permeation film forming test equipment as claimed in claim 3, characterized in that: The air pressure device includes an air compressor and a pressure stabilizing device connected to the air compressor to adjust the output air pressure of the air compressor, and all the pore pressure gauges are connected to the pressure stabilizing device.
6. The composite stratum mud-water shield slurry permeation film forming test equipment according to claim 1, characterized in that: The water supply device is a water supply funnel, the water inlet pipe is connected to the bottom of the water supply funnel, and the bottom elevation of the water supply funnel is higher than the initial elevation of the top surface of the soil sample layer.
7. The composite stratum mud-water shield slurry permeation film forming test equipment according to claim 1, characterized in that: The filter layer includes a geotextile laid on the lower cover and a quartz sand layer laid on the geotextile. The thickness and particle size of the quartz sand layer satisfy that the permeability of the filter layer is much higher than the permeability of the soil sample layer.