A vacuum pipeline control method for fine sand processing

Abstract

The present invention relates to the field of geotechnical engineering construction technology, and in particular to a vacuum pipeline control method for fine sand processing, including: obtaining basic parameters of the fine sand layer in the target area and determining the grouting range; determining the position and number of vertical drainage channels according to the grouting range, and arranging grouting pipelines between the vertical drainage channels; constructing a vacuum preloading environment and a grouting environment; determining the working stage of the vacuum pipeline based on the vacuum degree and drainage volume during the vacuuming process, including the vacuuming stage and the drainage stage; continuously monitoring the drainage volume and the content of grouting markers in the drainage, and controlling the start and stop of the vacuum pipeline according to the monitoring results. The present invention discharges the moisture in the fine sand layer through vacuuming through a vacuum pipeline, reduces the water content of the fine sand layer, and avoids the problems of large flow resistance of the slurry and poor penetration of the grouting slurry in the grouting process, thereby improving the uniformity of grouting.

Description

Technical Field

[0001] The invention relates to the technical field of geotechnical engineering construction, and in particular to a vacuum pipeline control method for fine sand processing. Background Art

[0002] Fine sand is a loose sediment formed in the Quaternary period, mainly referring to sandy soil with a particle size of less than 0.25 mm accounting for more than 50% of the total weight, and particles with a particle size of more than 0.075 mm accounting for more than 50% of the total mass. Fine sand in its natural state has poor cementation, loose structure, and low bearing capacity. It can be compacted under the action of its own weight. Under normal conditions, fine sand belongs to medium and high permeability strata. When fine sand is saturated with water, it is easy to disintegrate due to moisture, resulting in loss of overall structural properties. Grouting is a method of injecting certain curable slurries into cracks or pores of rock foundations to improve their physical and mechanical properties. Grouting of fine sand layers is relatively difficult. The fine sand layers themselves have low strength, and their pores and cracks are very small. Generally, suspended slurries are not easy to inject. The flow resistance of the slurry during the grouting process is very large. The grouting slurry is not easy to penetrate into the fine sand layer in the stratum, and the grouting uniformity is relatively poor, which cannot meet the requirements of soil reinforcement.

[0003] Chinese patent application publication number CN116537160A discloses a grouting method for a soil layer with small porosity, including: drilling a grouting hole on a target area based on a preset grouting hole position; the depth of the grouting hole is the position of the soil layer to be grouted; inserting a grouting pipe into the soil layer to be grouted through the grouting hole, and sealing the grouting hole opening; injecting gas into the grouting pipe based on pressure gas injection to increase the porosity of the soil layer to be grouted; using the infiltration grouting method, infiltration grouting is performed on the soil layer to be grouted through the grouting pipe; when the voids in the soil layer are completely filled with slurry, further pressure grouting is used to further expand the slurry to achieve the purpose of strengthening the soil body. The technical problems that the flow resistance of the slurry in the soil layer with small porosity is large during the grouting process, the grouting slurry is not easy to penetrate into the fine sand layer in the stratum, and the grouting uniformity is relatively poor are alleviated.

[0004] It can be seen that the vacuum negative pressure grouting method and device provided by the invention have the following problems: it is difficult to overcome the problem of poor grouting uniformity by only increasing the porosity through pressure gas injection and combining infiltration grouting and pressure grouting for grouting, and the grouting effect is average. Summary of the invention

[0005] To this end, the present invention provides a vacuum pipeline control method for fine sand processing, so as to overcome the problem of poor grouting uniformity in the prior art.

[0006] To achieve the above object, the present invention provides a vacuum pipeline control method for fine sand processing, comprising:

[0007] Step S1, obtaining basic parameters of the fine sand layer in the target area to determine the grouting range; the basic parameters of the fine sand layer include the depth of each position of the fine sand layer and the porosity of the fine sand layer;

[0008] Step S2, determining the position and number of vertical drainage channels according to the grouting range, and arranging grouting pipelines between the vertical drainage channels;

[0009] Step S3, connecting each of the vertical drainage channels with a vacuum pipeline to construct a vacuum preloading environment, and connecting each grouting pipeline with a grouting equipment to construct a grouting environment;

[0010] Step S4, determining the working stage of the vacuum pipeline based on the vacuum degree and the drainage volume during the vacuuming process, including the vacuuming stage and the drainage stage;

[0011] in,

[0012] Under the first condition, the working stage of the vacuum pipeline is the vacuum pumping stage, and the opening degree of the vacuum valve is determined according to the vacuum degree of the vacuum pipeline;

[0013] Under the second condition, the working stage of the vacuum pipeline is a drainage stage, and the opening of the vacuum valve is determined according to the drainage volume of the vacuum pipeline;

[0014] Step S5, continuously monitoring the drainage volume and the content of grouting markers in the drainage, and controlling the start and stop of the vacuum pipeline according to the monitoring results.

[0015] Furthermore, in the step S4, it also includes determining the grouting pressure of the grouting delivery according to the working stage of the vacuum pipeline, including pressure-regulated grouting and high-pressure grouting, wherein:

[0016] If the working stage of the vacuum pipeline is the vacuum pumping stage, it is determined that the grouting pressure of the grouting delivery is set to high-pressure grouting;

[0017] If the working stage of the vacuum pipeline is the drainage stage, it is determined that the grouting pressure of the grouting delivery is set to pressure-regulated grouting, and the grouting pressure of the pressure-regulated grouting is determined according to the surface settlement rate.

[0018] Furthermore, in step S4,

[0019] If the vacuum degree is greater than a preset vacuum degree threshold and the displacement is less than a first preset displacement threshold, it is determined that the first condition is met;

[0020] If the water displacement is not less than the first preset water displacement threshold, it is determined that the second condition is met.

[0021] Furthermore, in the step S4, the opening of the vacuum valve corresponding to the vacuum degree of the vacuum pipeline is determined according to a preset first comparison table.

[0022] Furthermore, in the step S4, the opening of the vacuum valve corresponding to the water discharge of the vacuum pipeline is determined according to a preset second comparison table.

[0023] Furthermore, in step S5, if the drainage volume is greater than a second preset drainage volume threshold, or the grouting marker content in the drainage is greater than a first preset marker content threshold, the vacuum pipeline is controlled to stop working.

[0024] Furthermore, in the step S5, it also includes determining whether the grouting is completed according to the drainage volume and the grouting volume after the vacuum pipeline stops working.

[0025] Furthermore, if the drainage volume is greater than a second preset drainage volume threshold, the grouting marker content in the drainage is less than a first preset marker content threshold and greater than a second preset marker content threshold, and the grouting volume is greater than the drainage volume, it is determined that the grouting is completed.

[0026] Furthermore, in the step S1, the fine sand layer region corresponding to the fine sand layer having a porosity greater than a preset porosity threshold is determined as a grouting range.

[0027] Further, in the step S2, the number N of the vertical drainage channels is determined according to the area S and the maximum radial length L of the grouting range, each of the vertical drainage channels is evenly distributed along the maximum radial direction of the grouting range, and the depth of each vertical drainage channel is determined according to the depth of each position of the fine sand layer;

[0028] Among them, N=S / (L*L / k), k is the first coefficient.

[0029] Compared with the prior art, the beneficial effect of the present invention is that the present invention obtains the basic parameters of the fine sand layer in the target area, determines the grouting range, determines the position and number of the vertical drainage channels according to the grouting range, and arranges the grouting pipelines between the vertical drainage channels, which can save energy, avoid waste of resources, and improve grouting efficiency. Each of the vertical drainage channels is connected to a vacuum pipeline to construct a vacuum preloading environment, and each grouting pipeline is connected to a grouting device to construct a grouting environment. The working stage of the vacuum pipeline is determined based on the vacuum degree and drainage volume during the vacuuming process, including the vacuuming stage and the drainage stage. The vacuum pipeline is used to construct a negative pressure environment, which can quickly drain the moisture in the fine sand layer and reduce the water content of the fine sand layer, so as to avoid the problems of large flow resistance of the slurry and poor penetration of the grouting slurry in the grouting process, thereby improving the uniformity of grouting. Continuously monitoring the drainage volume and controlling the start and stop of the vacuum pipeline according to the monitoring results can timely avoid the problem that the water content of the fine sand layer is too low, resulting in too small porosity, which leads to the grouting slurry being difficult to penetrate, thereby ensuring the uniformity of grouting. In addition, monitoring the content of grouting markers in the drainage can timely detect the penetration effect of the grouting slurry, avoid discharging the grouting slurry as water by mistake, affecting the grouting effect, and saving energy.

[0030] Furthermore, the present invention performs grouting during the vacuuming process. High-pressure grouting during the vacuuming stage can improve the grouting efficiency. Pressure-adjusted grouting during the drainage stage can avoid the problem of slurry being difficult to penetrate due to reduced water content in the fine sand layer.

[0031] Furthermore, the working stage of the vacuum pipeline is determined based on the vacuum degree and the drainage volume during the vacuum pumping process. Adjusting the opening of the vacuum valve can control the exhaust volume of the vacuum pump to improve working efficiency, and can also avoid the problem of excessive drainage caused by excessive opening of the vacuum valve during the drainage stage.

[0032] Furthermore, the drainage volume being greater than the second preset drainage volume threshold value indicates that the moisture content of the fine sand layer is close to the critical point. Further drainage will cause the permeability of the grouting slurry to the fine sand layer to decrease. The grouting marker content in the drainage volume being greater than the first preset marker content threshold value, indicating that the grouting slurry is mistakenly discharged as water. It is necessary to control the vacuum pipeline to stop working to avoid grouting failure caused by other factors.

[0033] Furthermore, the drainage volume is greater than the second preset drainage volume threshold, indicating that the moisture content of the silt sand layer is close to the critical point, and the grouting marker content in the drainage is less than the first preset marker content threshold and greater than the second preset marker content threshold, indicating that during the drainage process, a certain amount of grouting slurry has penetrated into the vertical drainage channel but not too much grouting slurry is discharged with the water. The grouting volume is greater than the drainage volume, indicating that a large amount of grouting slurry has replaced the original moisture and penetrated into the silt sand layer and increased the consolidation degree of the silt sand layer.

[0034] Furthermore, the fine sand layer region corresponding to the porosity of the fine sand layer being greater than a preset porosity threshold is unstable, has a loose structure, and has a low bearing capacity, and grouting is required to increase the stability of the fine sand layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic diagram of the steps of the vacuum pipeline control method for fine sand processing according to the present invention;

[0036] Figure 2 It is a structural schematic diagram of the vacuum preloading environment of the present invention;

[0037] Figure 3 It is a flow chart of the working phase of the vacuum pipeline of the present invention in the vacuum pumping phase;

[0038] Figure 4 It is a flow chart of the working stage of the vacuum pipeline of the present invention in the drainage stage;

[0039] In the figure: 1. vacuum pipeline; 2. vertical drainage channel; 3. drainage outlet; 4. vacuum chamber; 5. vacuum pump; 6. detection mechanism; 7. vacuum valve. DETAILED DESCRIPTION

[0040] In order to make the objects and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0041] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the protection scope of the present invention.

[0042] It should be noted that, in the description of the present invention, terms such as "up", "down", "left", "right", "inside" and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings. This is merely for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0043] In addition, it should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0044] See also Figure 1 , Figure 3 and Figure 4 As shown, Figure 1 This is a schematic diagram of the steps of the vacuum pipeline control method for fine sand processing according to the present invention. Figure 3 This is a flow chart of the vacuum pipeline in the vacuum pumping stage of the present invention. Figure 4 The figure is a flow chart of the working phase of the vacuum pipeline of the present invention during the drainage phase.

[0045] The present invention provides a vacuum pipeline control method for fine sand processing, comprising:

[0046] Step S1, obtaining basic parameters of the fine sand layer in the target area to determine the grouting range; the basic parameters of the fine sand layer include the depth of each position of the fine sand layer and the porosity of the fine sand layer;

[0047] Specifically, the basic parameters of the silt sand layer also include: permeability coefficient, water content, dry density, etc.; the depth of each position of the silt sand layer includes the depth of each position of the upper surface layer of the silt sand layer and the depth of each position of the lower surface layer, wherein the water content is the ratio of the volume occupied by water in the silt sand layer to the total volume of the silt sand layer.

[0048] Specifically, in the step S1, the fine sand layer region corresponding to the fine sand layer having a porosity greater than a preset porosity threshold is determined as the grouting range.

[0049] In practice, the fine sand layer area corresponding to the porosity of the fine sand layer being greater than the preset porosity threshold is unstable, has a loose structure, and has a low bearing capacity, and grouting is required to increase the stability of the fine sand layer.

[0050] In actual application scenarios, actual implementers can set a preset porosity threshold according to actual conditions. Generally, the value range of the preset porosity threshold can be set to 0.2-0.4. Preferably, the value of the preset porosity threshold is 0.2.

[0051] Step S2, determining the position and number of vertical drainage channels according to the grouting range, and arranging grouting pipelines between the vertical drainage channels;

[0052] Specifically, in step S2, the number N of the vertical drainage channels is determined according to the area S and the maximum radial length L of the grouting range, each of the vertical drainage channels is evenly distributed along the maximum radial direction of the grouting range, and the depth of each vertical drainage channel is determined according to the depth of each position of the fine sand layer;

[0053] Wherein, N=S / (L×L / k), k is the first coefficient.

[0054] In practice, according to the area S (unit: m 2 ) and the maximum radial length L (unit: m) can be used to calculate the number N of vertical drainage channels, the bottom end of the vertical drainage channel is arranged on the lower surface layer of the fine sand layer, and a plurality of drainage outlets are arranged on each vertical drainage channel. A filter net is arranged at each drainage outlet to filter the fine sand to prevent the fine sand from being brought out during drainage, affecting the stability of the fine sand layer and preventing the fine sand from blocking the drainage outlet.

[0055] It should be noted that the first coefficient can be set by the actual implementation personnel based on the expert system according to the actual situation, or determined according to the area of ​​the grouting range. The value range of the first coefficient can be 1-2.5 times.

[0056] Step S3, connecting each of the vertical drainage channels with a vacuum pipeline to construct a vacuum preloading environment, and connecting each grouting pipeline with a grouting equipment to construct a grouting environment;

[0057] In implementation, see Figure 2 As shown, it is a structural schematic diagram of a vacuum preloading environment provided by the present invention. In the vacuum preloading environment, the vertical drainage channel 2 is connected to the vacuum pipeline 1, and a plurality of drainage ports 3 are arranged at the lower end of the vertical drainage channel deep underground. The vacuum pipeline is connected to the vacuum drainage equipment, and the vacuum drainage equipment includes a vacuum chamber 4, a vacuum pump 5, a detection mechanism 6, and a vacuum valve 7; the detection mechanism 6 includes a vacuum gauge and a grouting marker detection component. In addition, each grouting pipeline in the grouting environment is connected to the grouting equipment, and the grouting equipment includes a grouting pump and a grouting source.

[0058] Step S4, determining the working stage of the vacuum pipeline based on the vacuum degree and the drainage volume during the vacuuming process, including the vacuuming stage and the drainage stage;

[0059] in,

[0060] Under the first condition, the working stage of the vacuum pipeline is the vacuum pumping stage, and the opening degree of the vacuum valve is determined according to the vacuum degree of the vacuum pipeline;

[0061] Under the second condition, the working stage of the vacuum pipeline is a drainage stage, and the opening of the vacuum valve is determined according to the drainage volume of the vacuum pipeline;

[0062] Specifically, in step S4,

[0063] If the vacuum degree is greater than a preset vacuum degree threshold and the displacement is less than a first preset displacement threshold, it is determined that the first condition is met;

[0064] If the water displacement is not less than the first preset water displacement threshold, it is determined that the second condition is met.

[0065] It is understandable that in actual application scenarios, the actual implementer can set the preset vacuum threshold and the first preset drainage threshold according to the actual situation. The larger the value of the preset vacuum threshold, the higher the vacuum requirement for the vacuum stage. Preferably, the value range of the preset vacuum threshold can be set to 70kPa-100kPa. The first preset drainage threshold can be calculated according to the moisture content H of the fine sand layer. Preferably, the first preset drainage threshold can be set to In the range, V is the total volume of fine sand layer in the grouting range (unit: m 3 ); ρ is the density of water (unit: kg / m 3 ).

[0066] Specifically, in step S4, the opening degree of the vacuum valve corresponding to the vacuum degree of the vacuum pipeline is determined according to a preset first comparison table.

[0067] In implementation, the actual implementation personnel can set the preset first comparison table based on the expert system according to the actual situation. For example, when the vacuum degree is 0-20kPa, the opening of the vacuum valve is set to 95%-100%; when the vacuum degree is 20kPa-40kPa, the opening of the vacuum valve is set to 90%-95%; when the vacuum degree is 40kPa-70kPa, the opening of the vacuum valve is set to 80%-90%; when the vacuum degree is 70kPa-100kPa, the opening of the vacuum valve is set to 60%-80%; when the vacuum degree is For vacuum levels of 100kPa-120kPa, set the opening of the vacuum valve to 40%-60%; for vacuum levels of 120kPa-125kPa, set the opening of the vacuum valve to 30%-40%; for vacuum levels of 125kPa-130kPa, set the opening of the vacuum valve to 20%-30%; for vacuum levels of 130kPa-135kPa, set the opening of the vacuum valve to 10%-20%; for vacuum levels of 135kPa-140kPa and above, set the opening of the vacuum valve to 0-10%.

[0068] Specifically, in step S4, the opening of the vacuum valve corresponding to the water discharge volume of the vacuum pipeline is determined according to a preset second comparison table.

[0069] In implementation, the actual implementation personnel can set the preset second comparison table based on the expert system according to the actual situation. For example, if the water discharge is 0-10kg, the opening of the vacuum valve is set to 95%-100%; if the water discharge is 10kg-50kg, the opening of the vacuum valve is set to 90%-95%; if the water discharge is 50kg-100kg, the opening of the vacuum valve is set to 80%-90%; if the water discharge is 100kg-200kg, the opening of the vacuum valve is set to 60%-80%; If the displacement is 200kg-350kg, the opening of the vacuum valve is set to 40%-60%; if the displacement is 350kg-500kg, the opening of the vacuum valve is set to 30%-40%; if the displacement is 500kg-700kg, the opening of the vacuum valve is set to 20%-30%; if the displacement is 700kg-900kg, the opening of the vacuum valve is set to 10%-20%; if the displacement is 900kg-1000kg and above, the opening of the vacuum valve is set to 0-10%.

[0070] In implementation, the working stage of the vacuum pipeline is determined based on the vacuum degree and drainage volume during the vacuum pumping process. Adjusting the opening of the vacuum valve can control the exhaust volume of the vacuum pump to improve working efficiency, and can also avoid the problem of excessive drainage caused by excessive opening of the vacuum valve during the drainage stage.

[0071] Specifically, in the step S4, it also includes determining the grouting pressure of the grouting delivery according to the working stage of the vacuum pipeline, including pressure-regulated grouting and high-pressure grouting, wherein:

[0072] If the working stage of the vacuum pipeline is the vacuum pumping stage, it is determined that the grouting pressure of the grouting delivery is set to high-pressure grouting;

[0073] If the working stage of the vacuum pipeline is the drainage stage, it is determined that the grouting pressure of the grouting delivery is set to pressure-regulated grouting, and the grouting pressure of the pressure-regulated grouting is determined according to the surface settlement rate.

[0074] During implementation, during the vacuum stage, the vacuum degree is relatively low, and the permeability of the fine sand layer is not high. Only based on normal pressure grouting, the injected slurry flows and penetrates along the pores and the direction of the least resistance. The flow direction and distribution of the slurry are completely random, resulting in uneven grouting. Therefore, it is necessary to set the grouting pressure of grouting transportation to high-pressure grouting; during the drainage stage, the vacuum degree is relatively high, but due to the increase in drainage volume and the influence of surface subsidence, the grouting pressure is too low, and the slurry is difficult to inject. When the grouting pressure is too high, the fine sand layer will crack and crack, causing the slurry to be injected along the cracks. Therefore, the grouting pressure of grouting transportation is set to pressure-regulated grouting, and the grouting pressure of pressure-regulated grouting is determined according to the surface subsidence rate.

[0075] It should be noted that the grouting pressure of the high-pressure grouting is greater than the first preset grouting pressure and less than the second preset grouting pressure. The first preset grouting pressure and the second preset grouting pressure can be set by the actual implementation personnel according to the actual situation. Generally, the first preset grouting pressure can be set to 200kPa-300kPa; the second preset grouting pressure can be set to 500kPa-600kPa. The grouting pressure YL of the pressure-regulated grouting can be obtained by the following method: YL=v 2 ×g×C, where v is the surface sedimentation velocity (unit: m / s), C is the flow coefficient (unit: kg / m 3 ), g is the second coefficient; the flow coefficient can be set by the actual implementer according to the actual situation and is related to the properties of the grouting material.

[0076] The present invention performs grouting during the vacuuming process. High-pressure grouting in the vacuuming stage can improve the grouting efficiency. Pressure-adjusted grouting in the drainage stage can avoid the problem of slurry being difficult to penetrate due to reduced water content of the fine sand layer.

[0077] Step S5, continuously monitoring the drainage volume and the content of grouting markers in the drainage, and controlling the start and stop of the vacuum pipeline according to the monitoring results.

[0078] Specifically, in step S5, if the drainage volume is greater than a second preset drainage volume threshold, or the grouting marker content in the drainage is greater than a first preset marker content threshold, the vacuum pipeline is controlled to stop working.

[0079] In implementation, the drainage volume being greater than the second preset drainage volume threshold value indicates that the moisture content of the fine sand layer is close to the critical point. Further drainage will cause the permeability of the grouting slurry to the fine sand layer to decrease. The grouting marker content in the drainage volume being greater than the first preset marker content threshold value, indicating that the grouting slurry is mistakenly discharged as water. It is necessary to control the vacuum pipeline to stop working to avoid grouting failure caused by other factors.

[0080] Specifically, the grouting markers can be set by the actual implementers based on the composition of the grouting slurry according to actual conditions. They can be any component in the grouting slurry that can be carried by the discharged water, such as cement, water glass, fly ash, slag or fine sand particles with a diameter of less than 1 mm. The particle size of the grouting markers is sufficient to be discharged from the grouting pores.

[0081] Specifically, in the step S5, it also includes determining whether the grouting is completed according to the drainage volume and the grouting volume after the vacuum pipeline stops working.

[0082] Specifically, if the drainage volume is greater than a second preset drainage volume threshold, the grouting marker content in the drainage is less than a first preset marker content threshold and greater than a second preset marker content threshold, and the grouting volume is greater than the drainage volume, then the grouting is determined to be completed.

[0083] In implementation, the drainage volume is greater than the second preset drainage volume threshold, indicating that the moisture content of the fine sand layer is close to the critical point, and the grouting marker content in the drainage is less than the first preset marker content threshold and greater than the second preset marker content threshold, indicating that during the drainage process, a certain amount of grouting slurry has penetrated into the vertical drainage channel but not too much grouting slurry is discharged with the water. The grouting volume is greater than the drainage volume, indicating that a large amount of grouting slurry has replaced the original moisture and penetrated into the fine sand layer and increased the consolidation degree of the fine sand layer.

[0084] It should be noted that the second preset drainage threshold can be calculated according to the moisture content of the fine sand layer. Preferably, the second preset drainage threshold can be set to Within the range, the first preset marker content threshold value and the second preset marker content threshold value can be calculated according to the content QZ of the grouting marker in the injected grouting slurry (the proportion of the grouting marker in the grouting slurry can be determined when the grouting slurry is prepared) (unit: kg). Generally, the first preset marker content threshold value can be set to 0.01 times-0.001 times of QZ, and the first preset marker content threshold value can be set to 0.0005 times-0.0008 times of QZ.

[0085] The present invention obtains the basic parameters of the fine sand layer in the target area, determines the grouting range, determines the position and number of the vertical drainage channels according to the grouting range, and arranges the grouting pipelines between the vertical drainage channels, which can save energy, avoid resource waste, and improve grouting efficiency. Each of the vertical drainage channels is connected to a vacuum pipeline to construct a vacuum preloading environment, and each grouting pipeline is connected to a grouting device to construct a grouting environment. The working stage of the vacuum pipeline is determined based on the vacuum degree and the drainage volume during the vacuuming process, including the vacuuming stage and the drainage stage. The vacuum pipeline is used to construct a negative pressure environment, which can quickly drain the moisture in the fine sand layer and reduce the water content of the fine sand layer, so as to avoid the problems of large flow resistance of the slurry and poor penetration of the grouting slurry in the grouting process, thereby improving the uniformity of grouting. Continuously monitoring the drainage volume and controlling the start and stop of the vacuum pipeline according to the monitoring results can timely avoid the problem that the water content of the fine sand layer is too low, resulting in too small porosity, which leads to the grouting slurry being difficult to penetrate, thereby ensuring the uniformity of grouting. In addition, monitoring the content of grouting markers in the drainage can timely detect the penetration effect of the grouting slurry, avoid discharging the grouting slurry as water by mistake, affecting the grouting effect, and saving energy.

[0086] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims

1. A vacuum pipeline control method for fine sand processing, characterized in that: include: Step S1, obtaining basic parameters of the fine sand layer in the target area to determine the grouting range; the basic parameters of the fine sand layer include the depth of each position of the fine sand layer and the porosity of the fine sand layer; Step S2, determining the position and number of vertical drainage channels according to the grouting range, and arranging grouting pipelines between the vertical drainage channels; Wherein, each of the vertical drainage channels is evenly distributed along the maximum radial direction of the grouting range; Step S3, connecting each of the vertical drainage channels with a vacuum pipeline to construct a vacuum preloading environment, and connecting each grouting pipeline with a grouting equipment to construct a grouting environment; Step S4, determining the working stage of the vacuum pipeline based on the vacuum degree and the drainage amount during the vacuuming process, including the vacuuming stage and the drainage stage; Wherein, under the first condition, the working stage of the vacuum pipeline is the vacuum pumping stage, and the opening degree of the vacuum valve is determined according to the vacuum degree of the vacuum pipeline; Under the second condition, the working stage of the vacuum pipeline is a drainage stage, and the opening of the vacuum valve is determined according to the drainage volume of the vacuum pipeline; In the step S4, it also includes determining the grouting pressure of the grouting delivery according to the working stage of the vacuum pipeline, including pressure-regulated grouting and high-pressure grouting, wherein: If the working stage of the vacuum pipeline is the vacuum pumping stage, it is determined that the grouting pressure of the grouting delivery is set to high-pressure grouting; If the working stage of the vacuum pipeline is the drainage stage, it is determined that the grouting pressure of the grouting delivery is set to the pressure-regulated grouting, and the grouting pressure of the pressure-regulated grouting is determined according to the surface settlement rate; Step S5, continuously monitoring the drainage volume and the content of grouting markers in the drainage, and controlling the start and stop of the vacuum pipeline according to the monitoring results.

2. The vacuum pipeline control method for fine sand processing according to claim 1 is characterized in that: In step S4, If the vacuum degree is greater than a preset vacuum degree threshold and the displacement is less than a first preset displacement threshold, it is determined that the first condition is met; If the water displacement is not less than the first preset water displacement threshold, it is determined that the second condition is met.

3. The vacuum pipeline control method for fine sand processing according to claim 2 is characterized in that: In the step S4, the opening degree of the vacuum valve corresponding to the vacuum degree of the vacuum pipeline is determined according to a preset first comparison table.

4. The vacuum pipeline control method for fine sand processing according to claim 3 is characterized in that: In the step S4, the opening of the vacuum valve corresponding to the water discharge volume of the vacuum pipeline is determined according to a preset second comparison table.

5. The vacuum pipeline control method for fine sand processing according to claim 4 is characterized in that: In step S5, if the drainage volume is greater than a second preset drainage volume threshold, or the grouting marker content in the drainage is greater than a first preset marker content threshold, the vacuum pipeline is controlled to stop working.

6. The vacuum pipeline control method for fine sand processing according to claim 5 is characterized in that: In the step S5, it also includes determining whether the grouting is completed according to the drainage volume and the grouting volume after the vacuum pipeline stops working.

7. The vacuum pipeline control method for fine sand processing according to claim 6 is characterized in that: If the drainage volume is greater than the second preset drainage volume threshold, the grouting marker content in the drainage is less than the first preset marker content threshold and greater than the second preset marker content threshold, and the grouting volume is greater than the drainage volume, then the grouting is determined to be completed.

8. The vacuum pipeline control method for fine sand processing according to claim 1 is characterized in that: In the step S1, the fine sand layer region corresponding to the fine sand layer having a porosity greater than a preset porosity threshold is determined as a grouting range.

9. The vacuum pipeline control method for fine sand processing according to claim 1, characterized in that: In the step S2, the number N of the vertical drainage channels is determined according to the area S of the grouting range and the maximum radial length L, and the depth of each vertical drainage channel is determined according to the depth of each position of the fine sand layer; Among them, N=S / (L*L / k), k is the first coefficient.

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