Negative pressure grouting construction technology for broken strata

Abstract

The present invention provides a negative pressure grouting construction process for crushing strata, comprising the following steps: determining the distribution range of the curtain wall, setting at least one row of grouting hole groups on both sides of the distribution range, each row of the grouting hole groups comprising a plurality of grouting holes distributed along the extension direction of the distribution range; defining three adjacent grouting holes distributed in a triangular shape as a grouting unit, and setting a negative pressure hole at the outer center of the grouting unit; filling the plurality of grouting holes with prefabricated slurry; and evacuating the negative pressure holes to form a negative pressure environment until slurry seeps out of the negative pressure holes. In the negative pressure grouting construction process for crushing strata provided by the present invention, when grouting from the grouting holes, the negative pressure holes pump liquid outward, and the negative pressure effect of the negative pressure holes guides the diffusion of the slurry, thereby preventing the slurry from randomly spreading around the grouting holes.

Description

Technical Field

[0001] The invention belongs to the technical field of mine curtain wall grouting construction, and particularly relates to a negative pressure grouting construction process for broken strata. Background Art

[0002] With the increasing development of mines, the mining depth has continued to deepen, gradually shifting from the surface to underground, and from shallow to deep. Groundwater has also become an important factor affecting the safe mining of mines. Due to some reasons, the waste treatment facilities of old mines in China are incomplete, outdated, and damaged parts are not updated in time, resulting in varying degrees of weakening of their functions, causing pollution to nearby groundwater and soil, and affecting the ecological environment.

[0003] Currently, the treatment of groundwater and waste in mines often relies on curtain wall grouting. This method utilizes the pores, cracks, and broken areas of the stratum to press slurry into the stratum at a certain pressure. The slurry and the stratum undergo cementation, filling, and compaction. The solidified slurry blocks the pores and cracks in the stratum rock mass, forming a continuous curtain wall to achieve reinforcement and anti-seepage effects. The curtain wall is a wall structure formed in the vertical direction. However, in the existing technology, the diffusion range of the slurry is difficult to control when grouting in broken strata. The actual diffusion range is far greater than the preset diffusion range, resulting in slurry consumption far exceeding the project requirements and high construction costs. Summary of the Invention

[0004] The embodiment of the present invention provides a negative pressure grouting construction process for broken strata, aiming to solve the problem in the prior art that the diffusion range of slurry is difficult to control, resulting in excessive slurry usage and high construction costs.

[0005] To achieve the above object, the technical solution adopted by the present invention is to provide a negative pressure grouting construction process for broken strata, comprising the following steps:

[0006] Determine the distribution range of the curtain wall, and set at least one row of grouting hole groups on both sides of the distribution range, each row of the grouting hole groups includes a plurality of grouting holes distributed along the extension direction of the distribution range;

[0007] The three adjacent grouting holes distributed in a triangle are defined as a grouting unit, and a negative pressure hole is provided at the outer center of the grouting unit;

[0008] Filling the plurality of grouting holes with prefabricated slurry;

[0009] The negative pressure hole is evacuated to form a negative pressure environment until slurry seeps out of the negative pressure hole.

[0010] In a possible implementation, two adjacent grouting units share two grouting holes, and the two shared grouting holes are respectively located in two adjacent rows of grouting hole groups.

[0011] In a possible implementation, the plurality of grouting holes are arranged in a staggered manner in a plum blossom shape or in parallel in a rectangular shape.

[0012] In one possible implementation, the opening of the negative pressure hole is provided with a sealing cover, and the sealing cover is provided with a pressure pump and a vacuum device respectively connected to the negative pressure hole, the pressure pump is used to extract the liquid in the negative pressure hole until the prefabricated slurry is extracted, and the vacuum device is used to provide a negative pressure environment.

[0013] In a possible implementation, the density ρ of the seepage slurry pumped out by the pressure pump is obtained, and when ρ is substantially the same as the density ρ0 of the prefabricated slurry injected into the grouting hole, the pressure pump is turned off.

[0014] In a possible implementation, the opening of the negative pressure hole is provided with a groove, and the sealing cover is provided in the groove;

[0015] The sealing cover is provided with a vacuum tube connected to the vacuum device and a pressure extraction tube connected to the pressure pump;

[0016] An inner lining tube is provided in the negative pressure hole, and a through hole is provided at a position at the lower portion of the inner lining tube corresponding to the penetration area of the negative pressure hole.

[0017] In a possible implementation, a sealer is provided at the opening of the grouting hole;

[0018] The sealer is provided with a grouting pipe and a slurry outlet pipe respectively connected to the grouting holes;

[0019] The hole wall of the grouting hole is the original rock layer wall.

[0020] In one possible implementation, the grouting unit and the corresponding negative pressure hole are defined as a construction unit, and multiple construction units are constructed in a preset order. The construction steps include: filling the multiple grouting holes with prefabricated slurry in turn, and evacuating the negative pressure hole to form a negative pressure environment until slurry seeps out of the negative pressure hole.

[0021] In a possible implementation, a negative pressure test operation is performed on the construction unit after construction, and the negative pressure test operation specifically includes:

[0022] The prefabricated slurry in the negative pressure hole is extracted and filled with water, and the negative pressure hole is obtained after an interval of 2 to 4 hours;

[0023] Providing a negative pressure environment to the negative pressure water injection hole, and observing the water output w per unit time of the negative pressure water injection hole;

[0024] The obtained water output w is compared with the water output w1 required by the design. If w<w1, the grouting of the construction unit where the negative pressure hole is located is judged to be qualified. If w≥w1, the grouting of the construction unit where the negative pressure hole is located is judged to be unqualified.

[0025] In a possible implementation, the unqualified construction unit is re-injected with slurry, and prefabricated slurry is re-injected through the negative pressure hole and the grouting hole. After the construction unit is re-injected, the above-mentioned negative pressure test operation is repeated until w<w1.

[0026] The negative pressure grouting construction process for broken strata provided by the present invention, compared with the prior art, is characterized in that grouting hole groups are arranged on both sides of a preset curtain wall, three grouting holes are divided into a grouting unit, and a negative pressure hole is arranged at the circumcenter position of the grouting unit. When grouting is carried out from the grouting hole, the negative pressure hole draws liquid outward, and the suction force of the negative pressure hole gives the slurry an attraction to diffuse toward the negative pressure hole. The diffusion of the slurry is guided by the negative pressure effect of the negative pressure hole, and the slurry is prevented from randomly diffusing around the grouting hole. While ensuring the grouting effect and meeting the requirements of the curtain wall, the cost of the slurry used is greatly saved and the material investment is reduced; the diffusion of the slurry guided by the negative pressure hole also improves the overlap effect between the grouting holes and the uniformity of the curtain wall, and can more accurately control the thickness of the curtain wall to a certain extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0028] Figure 1 Schematic diagram of the negative pressure grouting construction process for broken strata provided in Example 1 of the present invention Figure 1 ;

[0029] Figure 2 Schematic diagram of the negative pressure grouting construction process for broken strata provided in Example 1 of the present invention Figure 2 ;

[0030] Figure 3 This is a schematic diagram of the assembly of the sealing cover and the working tube used in Example 1 of the present invention;

[0031] Figure 4 This is a structural diagram of a flower tube used in Example 1 of the present invention;

[0032] Figure 5A schematic diagram of a formed curtain wall provided in Example 1 of the present invention;

[0033] Figure 6 Schematic diagram of the negative pressure grouting construction process for broken strata provided in the second embodiment of the present invention.

[0034] Description of reference numerals:

[0035] 1. Grouting hole; 11. Sealer; 12. Grouting pipe; 13. Grouting pipe;

[0036] 2. Negative pressure hole; 21. Groove; 22. Vacuum tube; 23. Pumping tube; 24. Lining tube; 25. Flower tube;

[0037] 3. Vacuum device;

[0038] 4. Sealing cover;

[0039] 5. Pressure pump;

[0040] 6. Stop valve;

[0041] 7. Pressure sensor;

[0042] 8. Density sensor. DETAILED DESCRIPTION

[0043] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0044] It should be noted that the terms "length", "width", "height", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "head", "tail", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as a limitation on the invention.

[0045] It should also be noted that, unless otherwise expressly specified or limited, terms such as "installed," "connected," "connect," "fixed," and "set" should be understood broadly. For example, they may refer to fixed or detachable connections, or integration; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and may encompass internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of these terms in the present invention based on specific circumstances.

[0046] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features being referenced. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of such features. Furthermore, "plurality" and "several" mean two or more, unless otherwise specifically defined.

[0047] Please also refer to Figures 1 to 3 The negative pressure grouting construction process for crushed strata provided by the present invention is now described. The negative pressure grouting construction process for crushed strata includes the following steps: determining the distribution range of the curtain wall, setting at least one row of grouting hole groups on both sides of the distribution range, each row of grouting hole groups including a plurality of grouting holes 1 distributed along the extension direction of the distribution range; defining three adjacent grouting holes 1 distributed in a triangular shape as a grouting unit, and setting a negative pressure hole 2 at the outer center of the grouting unit; filling the plurality of grouting holes 1 with prefabricated slurry; and evacuating the negative pressure holes 2 to form a negative pressure environment until slurry seeps out of the negative pressure holes 2.

[0048] It should be noted that the grouting hole 1 and the negative pressure hole 2 in this embodiment are both straight tube-type through holes opened in the up and down directions. The original rock is exposed in the grouting hole 1, and the slurry can diffuse into the negative pressure hole 2 through the cracks in the original rock, providing a slurry source for the extraction of liquid from the negative pressure hole 2.

[0049] It should be noted that the stratum is divided into a construction section and a grouting section in sequence along the up and down directions, and the slurry can diffuse in the grouting section to form a curtain wall.

[0050] It should be noted that Figure 2 The arrows in the figure represent the flow paths of the slurry.

[0051] It is important to understand that Figure 1 and Figure 5 The shaded part in the figure is the formed curtain wall.

[0052] It should be noted that the three grouting holes 1 belong to two adjacent rows of grouting hole groups respectively.

[0053] It should be noted that prefabricated slurry is different from seepage slurry. Prefabricated slurry is pre-mixed slurry used to form curtain walls. There is groundwater in the stratum, and the seepage slurry extracted from the negative pressure hole 2 is a mixed slurry formed by mixing prefabricated downcomer and groundwater.

[0054] It should be noted that, in the process of groundwater being sucked out, the pores and cracks in the stratum will be closed to a certain extent, so the grouting hole 1 needs to be filled with slurry when the negative pressure hole 2 starts to provide negative pressure.

[0055] The negative pressure grouting construction process for broken strata provided in this embodiment, compared with the prior art, is in the following aspects: grouting hole groups are arranged on both sides of the preset curtain wall according to the length direction of the preset curtain wall, three grouting holes 1 are divided into a construction unit, and a negative pressure hole 2 is arranged at the circumcenter position of the construction unit. When grouting is performed from the grouting hole 1, liquid is pumped outward through the negative pressure hole 2, and the suction force of the negative pressure hole 2 gives the slurry an attraction to diffuse toward the negative pressure hole 2. The negative pressure effect of the negative pressure hole 2 guides the diffusion of the slurry, and avoids the slurry from randomly diffusing around the grouting hole 1. While ensuring the grouting effect and meeting the requirements of the curtain wall, the cost of the slurry used is greatly saved and the material investment is reduced; the provision of the negative pressure hole 2 also improves the overlap effect between the grouting holes 1 and the uniformity of the curtain wall, and can more accurately control the thickness of the curtain wall to a certain extent.

[0056] In some embodiments, see Figure 1 , two adjacent grouting units share two grouting holes 1, and the two shared grouting holes 1 are respectively located in two adjacent grouting hole groups. Figure 1 The grouting hole distribution in FIG is divided into multiple grouting units from bottom to top. Each grouting unit is a triangular structure. There are overlapping oblique sides between two adjacent grouting units, and there are two common grouting holes 1.

[0057] In the grouting unit of this embodiment, the negative pressure hole 2 is arranged inside the construction unit. The negative pressure hole 2 guides the slurry in the grouting hole 1 to gather toward the center. Therefore, the negative pressure hole 2 cannot guide the slurry on the side of the grouting hole 1 facing away from the negative pressure hole 2. After there is a common edge between adjacent construction units, the negative pressure hole 2 and the negative pressure holes 2 in the adjacent construction units cooperate to guide the slurry in all directions, ensuring that the slurry in the grouting hole 1 is guided by the negative pressure hole 2, so that the diffusion range and diffusion path of the slurry are controllable, thereby ensuring the diffusion effect of the slurry.

[0058] In some embodiments, the plurality of grouting holes 1 are arranged in a staggered manner in a plum blossom shape or in parallel in a rectangular shape.

[0059] Taking the example of multiple grouting holes 1 arranged in a staggered manner in a plum blossom shape, see Figure 1 In order to ensure that the distances from the negative pressure holes 2 to the three grouting holes 1 are equal, the two rows of grouting holes 1 are staggered and arranged in order. The two grouting holes 1 in the left row and the one grouting hole 1 in the right row are divided into a construction unit. The construction unit has a triangular structure, which is convenient for determining the circumcenter and thus facilitating the determination of the position of the negative pressure hole 2. During grouting, the negative pressure hole 2 can evenly guide the diffusion of the slurry in the three grouting holes 1, ensuring that the slurry diffusion effect in each grouting hole 1 is the same, saving slurry costs to the greatest extent.

[0060] Taking the multiple grouting holes 1 arranged in parallel in a rectangular shape as an example, see Figure 6, divide the four grouting holes 1 into a construction unit. The construction unit is a rectangle with the opposite sides of the rectangle arranged in parallel. The negative pressure hole 2 is arranged in the center of the construction unit to ensure that the distances between the negative pressure hole 2 and the four grouting holes 1 are equal, thereby ensuring that the attraction provided to the four grouting holes 1 is the same, thereby ensuring that the slurry in each grouting hole 1 is evenly diffused and improving the overlap effect between the grouting holes 1.

[0061] In some embodiments, see Figure 2 and Figure 3 The opening of the negative pressure hole 2 is provided with a sealing cover 4, and the sealing cover 4 is provided with a pressure pump 5 and a vacuum device 3 which are respectively connected to the negative pressure hole 2. The pressure pump 5 is used to extract the liquid in the negative pressure hole 2 until the prefabricated slurry is extracted, and the vacuum device 3 is used to provide a negative pressure environment. The vacuum device 3 extracts part of the air in the negative pressure hole 2, so that the negative pressure hole 2 forms a negative pressure environment with a certain vacuum degree. In the process of the vacuum device 3 providing negative pressure, the water in the negative pressure hole 2 is extracted by the pressure pump 5, and the prefabricated slurry flows into the negative pressure hole 2. When the prefabricated slurry is extracted by the pressure pump 5, it means that only the prefabricated slurry is left in the negative pressure hole 2, and the prefabricated slurry is evenly diffused into the negative pressure hole 2.

[0062] In some embodiments, the density of the slurry pumped out by the pressure pump 5 is tested to obtain the density ρ of the seepage slurry pumped out by the pressure pump 5. When ρ is approximately the same as the density ρ0 of the prefabricated slurry injected into the grouting hole 1, the pressure pump 5 is turned off. Since the slurry entering the negative pressure hole 2 is a mixture of the slurry injected into the grouting hole 1 and groundwater, its slurry density is different from the modulated slurry density. The slurry is pumped out by the pressure pump 5 so that the density ρ of the slurry remaining in the negative pressure hole 2 is approximately the same as the density ρ0 of the slurry injected into the grouting hole 1, thereby ensuring that the thickness of the curtain wall formed is consistent and improving the quality of the curtain wall.

[0063] In some embodiments, the pressure pump 5 applies pressure in stages, with the pressure applied at each stage being the same and the pressure stabilization time being the same. The pressure value and the stabilization time of each stage are the same, ensuring that the slurry in the negative pressure hole 2 is fully mixed after each pressurization. This avoids uneven slurry density caused by different pressurization times or values, which could affect the slurry density ρ and the comparison with the slurry density ρ0 injected into the grouting hole 1. The same pressure and the same stabilization time at each stage ensure that the obtained slurry density data is reliable and accurate.

[0064] In some embodiments, see Figure 3 and Figure 4The opening of the negative pressure hole 2 is provided with a groove 21, and a sealing cover 4 is provided in the groove 21; the sealing cover 4 is provided with a vacuum tube 22 connected to the vacuum device 3, and a pressure extraction tube 23 connected to the pressure pump 5; the negative pressure hole 2 is provided with an inner liner 24, and a through hole is provided at the lower part of the inner liner 24 at a position corresponding to the penetration area of the negative pressure hole 2. The slurry entering the negative pressure hole 2 enters through the through hole in the side wall of the inner liner 24, and the prefabricated slurry gradually fills the negative pressure hole 2 from bottom to top. The prefabricated slurry extracted by the pressure pump 5 can be used to determine that the prefabricated slurry has fully filled the negative pressure hole 2 and there is no groundwater in the negative pressure hole 2.

[0065] As an alternative arrangement for the inner liner 24, the negative pressure hole 2 is provided with a continuous, non-porous sleeve and a flower tube 25, arranged from top to bottom. The outer wall of the flower tube 25 is provided with multiple through-holes of varying diameters. The opening of the negative pressure hole 2 is sealed by a sealing cap 4, creating a sealed environment. This facilitates the vacuum device 3 and pressure pump 5 to change the vacuum level within the negative pressure hole 2, thereby providing a suction force to guide the diffusion of the slurry.

[0066] It should be noted that, see Figure 4 The outer periphery of the floral tube 25 is drilled with multiple through-holes at varying intervals. The floral tube 25 filters water and blocks sand. Slurry enters the floral tube 1 through the through-holes, filtering out impurities such as sand and gravel. This prevents impurities from being drawn into the negative pressure hole 2 and affecting the pressure pump 5 and vacuum device 3.

[0067] The non-porous sleeve and the flower tube 25 are arranged in sequence from top to bottom, so that the slurry entering the negative pressure hole 2 enters from the through hole on the side wall of the flower tube 25, and the slurry gradually fills the negative pressure hole 2 from bottom to top. The slurry gathers on the outer periphery of the flower tube 25 in the grouting section and then enters the negative pressure hole 2. The slurry can be completely diffused in the grouting section, avoiding uneven diffusion of the slurry in the grouting section, resulting in uneven thickness of the curtain wall formed, affecting the treatment effect.

[0068] In one embodiment of the arrangement of the floral tube 25 and the sleeve within the negative pressure hole 2, the through-holes in the floral tube 25 have a diameter of 5-10 mm, and the total surface area of the through-holes accounts for 30-50% of the total area of the tube wall. The bottom end of the pressure relief tube 24 is 100-300 mm from the bottom of the hole. A shutoff valve 6, a pressure sensor 7, and a density sensor 8 are sequentially positioned on the tube wall at one end of the pressure relief tube 24, located outside the sealing cover 4, along the direction of liquid withdrawal.

[0069] As a specific embodiment of the cooperation between the sealing cover 4 and the groove 21, see Figure 3An inverted trapezoidal groove 21 is opened at the mouth of the negative pressure hole 2, with a depth of 0.6m, a lower length and width of 0.5mm, and an upper length and width of 1m; a sealing cover 4 is set on the top of the non-porous casing, and the sealing cover 4 is an upward convex circular iron cover. The sealing cover 4 can be connected to the non-porous casing by threading. The middle of the circular iron cover is upward convex, and the surrounding areas are flat surfaces of a certain width, with a diameter of 0.3m and a height of 0.3m from the middle to the bottom; 0.3m of clay is backfilled in the groove 21 and vibrated to make it dense until the sealing cover 4 is in close contact with the clay; 0.1m of clay is backfilled on the top and vibrated to make it dense, and 0.1m of clay slurry is poured on the top to achieve sealing of the mouth of the negative pressure hole 2. A water injection sealer is used in the non-porous casing. One end of the water injection sealer is connected to the pressure pump 5 and the other end is connected to the vacuum device 3. The water injection sealer is lowered to the top of the grouting section. After pressurization and expansion, the upper part of the water injection sealer is filled with water until the top of the non-porous casing, thereby achieving the top sealing of the non-porous casing 23.

[0070] In some embodiments, see Figure 3 The opening of the grouting hole 1 is provided with a sealer 11; the sealer 1 is provided with a grouting pipe 12 and a slurry outlet pipe 13 respectively connected to the grouting hole 1; the hole wall of the grouting hole 1 is the original rock layer wall. In specific implementation, the process adopted for grouting the grouting hole 1 is a circulating grouting process, grouting from the grouting pipe 12 into the inside of the grouting hole 1 until slurry flows out of the slurry outlet pipe 13. The inner wall of the grouting hole 1 is the original rock wall, and the slurry can diffuse along the gaps in the original rock wall. The sealer 11 can seal the opening of the grouting hole 1, and can form a sealed space to cooperate with the negative pressure hole 2 to generate negative pressure, so as to facilitate the diffusion of slurry toward the negative pressure hole 2.

[0071] In specific implementation, a pressure sensor 7 and a density sensor 8 are respectively provided on the grouting pipe 12 and the slurry outlet pipe 13. The pressure in the grouting hole 1 is obtained by the pressure sensor 7, and the density of the slurry injected into the grouting hole 1 is obtained by the density sensor 8.

[0072] In some embodiments, the negative pressure hole 2 and the grouting hole 1 are vacuumed to form a closed space inside the negative pressure hole 2 and the grouting hole 1. In order to ensure that the negative pressure hole 2 can normally provide negative pressure and guide the slurry to spread, a vacuum device 3 is used to vacuum the space to ensure that when the negative pressure hole 2 provides negative pressure, the slurry can be guided by the suction force provided by the pressure pump 5. The vacuum degree in the negative pressure hole 2 and the grouting hole 1 is adjusted to ensure that the slurry spreads at the expected speed.

[0073] It should be noted that after the vacuum device 3 is turned on, the changes in the liquid levels of the slurry in the groove 21 and the non-porous sleeve 23 need to be observed. If the liquid level of the slurry decreases, it proves that the seal is not tight and needs to be re-sealed.

[0074] During the specific implementation, the negative pressure hole 2 is first washed, and the pressure pump 5 is used to extract the water retained in the negative pressure hole 2 after washing until no water flows out, and the stop valve 6 is closed; the vacuum device 3 provides negative pressure, and the vacuum degree in the pipe is 90-130Kpa. During this process, groundwater will continuously flow into the negative pressure hole 2; the pressure pump 5 regularly extracts groundwater in the negative pressure hole 2, and circulates in sequence until the vacuum degree in the negative pressure hole 2 is close to the design value.

[0075] In some embodiments, a grouting unit and the corresponding negative pressure hole 2 are defined as a construction unit. Multiple construction units are constructed in a preset order. The construction steps include: sequentially filling multiple grouting holes 1 with prefabricated slurry, evacuating the negative pressure hole 2 to form a negative pressure environment, until slurry seeps out of the negative pressure hole 2. The construction units are constructed sequentially. After the construction unit of the current construction is completed, the grouting operation of the adjacent construction unit is carried out. Each construction unit completes the grouting operation one by one, ensuring that the curtain wall portion corresponding to each construction unit is completed, and the overall curtain wall structure formed has consistent strength.

[0076] On the basis of the above embodiment, a negative pressure inspection operation is performed on the construction unit after construction, and the negative pressure inspection operation specifically includes: extracting the prefabricated slurry in the negative pressure hole 2 and filling it with water, and intermitting for 2 to 4 hours to obtain a water-injected negative pressure hole; providing a negative pressure environment for the water-injected negative pressure hole, and observing the water output w of the water-injected negative pressure hole per unit time; step three: comparing the obtained water output w with the water output w1 required by the design, if w<w1, it is judged that the grouting of the construction unit where the negative pressure hole 2 is located is qualified, and if w≥w1, it is judged that the grouting of the construction unit where the negative pressure hole 2 is located is unqualified.

[0077] Since the construction units are constructed in sequence, it is necessary to ensure the construction quality of each construction unit. Negative pressure inspection operations can detect unqualified construction units and prevent partial defects in the curtain wall after it is formed, which will affect the quality of the curtain wall.

[0078] In some embodiments, unqualified construction units are re-injected with slurry, and prefabricated slurry is re-injected through negative pressure hole 2 and grouting hole 1. After the construction unit is re-injected, the negative pressure test operation is repeated until w < w1. The unqualified construction units are re-injected to ensure that the curtain wall is of high quality and uniform thickness.

[0079] The following are specific examples of the embodiments of the present invention:

[0080] The construction project is the anti-seepage treatment of mine leachate. The site is a mountain valley. The rock types from top to bottom are plain fill, fully weathered mixed rock, strongly weathered mixed rock and moderately weathered mixed rock. The groundwater is mainly stored in the strong wind layer and below. The proposed anti-seepage curtain wall adopts curtain wall grouting. Two rows of grouting holes 1 are arranged on both sides of the curtain wall axis, with a row spacing of 1.5m and a hole spacing of 1.5m, in a plum blossom shape. According to hydrological data, below the fully weathered layer is a highly permeable layer with a thickness of about 10m. Negative pressure grouting construction technology is adopted in this layer.

[0081] Construction sequence: (1) The diameter of the opening is 160mm, the diameter of the lower casing is 146mm, and the casing + cement pipe is used in the fully weathered layer and above; the diameter is changed to 133mm below the highly permeable layer, and a 114mm casing is used. In the highly permeable layer, a flower pipe 24 with a hole diameter of 5mm is used, and 91 drilling is used.

[0082] (2) The opening of the negative pressure hole 2 is sealed with the above-mentioned "groove + backfill clay", and the inside of the hole is sealed with a 90mm water injection sealer. The vacuum device 3 provides negative pressure to check the effectiveness of the sealing measures, and it has passed the inspection.

[0083] (3) Negative pressure hole 2 provides negative pressure, with a designed vacuum degree of 120KPa, and is pressurized in three levels, 40KPa per level, and maintained at a constant pressure for 15 minutes per level; at the same time, the grouting hole 1 is filled with cement slurry with a water-cement ratio of 3:1, and circulated in the pressureless hole; the pressure pump 5 at the negative pressure hole 2 pumps water every 2 minutes until the vacuum degree in the hole reaches the designed value; the pressurization range of the grouting hole 1 is 0.1-0.3Mpa, and the pressure pump in the negative pressure hole 2 pumps slurry every 2 minutes until the density of the slurry in the negative pressure hole 2 is close to that of the slurry injected into the grouting hole 1, and the pressure pump 5 is turned off; until the slurry flows out of the vacuum pump outlet.

[0084] (4) Draw out the slurry in the negative pressure hole 2, fill it with water, and rest for 3 hours; perform negative pressure testing, observe the water output per unit time of the negative pressure hole 2 according to the designed vacuum degree, and the design requirement is less than 1L / min to be qualified. The first test flow rate is 10L / min. According to the injection volume of each grouting hole 1, the grouting hole 1 with the smallest injection volume is selected to be combined with the negative pressure hole 2 for re-injection; the second test flow rate is 0.83L / min, which meets the design requirements.

[0085] (5) Carry out the construction of each unit in sequence.

[0086] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A negative pressure grouting construction process for broken strata, characterized in that: The steps include: Determine the distribution range of the curtain wall, and set at least one row of grouting hole groups on both sides of the distribution range, each row of the grouting hole groups includes a plurality of grouting holes distributed along the extension direction of the distribution range; The three adjacent grouting holes distributed in a triangle are defined as a grouting unit, and a negative pressure hole is provided at the outer center of the grouting unit; Filling the plurality of grouting holes with prefabricated slurry; The negative pressure hole is evacuated to form a negative pressure environment until slurry seeps out of the negative pressure hole; Two adjacent grouting units share two grouting holes, and the two shared grouting holes are respectively located in two adjacent rows of grouting hole groups; The opening of the negative pressure hole is provided with a sealing cover, and the sealing cover is provided with a pressure pump and a vacuum device respectively connected to the negative pressure hole, the pressure pump is used to extract the liquid in the negative pressure hole until the prefabricated slurry is extracted, and the vacuum device is used to provide a negative pressure environment; The density ρ of the seepage slurry pumped out by the pressure pump is obtained, and when ρ is substantially the same as the density ρ0 of the prefabricated slurry injected into the grouting hole, the pressure pump is turned off.

2. The negative pressure grouting construction process for broken strata according to claim 1, characterized in that: The plurality of grouting holes are arranged in a staggered manner in a plum blossom shape or in parallel in a rectangular shape.

3. The negative pressure grouting construction process for broken strata according to claim 1, characterized in that: The opening of the negative pressure hole is provided with a groove, and the sealing cover is provided in the groove; The sealing cover is provided with a vacuum tube connected to the vacuum device and a pressure extraction tube connected to the pressure pump; An inner lining tube is provided in the negative pressure hole, and a through hole is provided at a position at the lower portion of the inner lining tube corresponding to the penetration area of the negative pressure hole.

4. The negative pressure grouting construction process for broken strata according to claim 1, characterized in that: The opening of the grouting hole is provided with a sealer; The sealer is provided with a grouting pipe and a slurry outlet pipe respectively connected to the grouting holes; The hole wall of the grouting hole is the original rock layer wall.

5. The negative pressure grouting construction process for broken strata according to claim 1, characterized in that: The grouting unit and the corresponding negative pressure hole are defined as a construction unit, and multiple construction units are constructed in a preset order. The construction steps include: filling the multiple grouting holes with prefabricated slurry in turn, and evacuating the negative pressure hole to form a negative pressure environment until slurry seeps out of the negative pressure hole.

6. The negative pressure grouting construction process for broken strata according to claim 5, characterized in that: Performing a negative pressure test on the construction unit after construction, the negative pressure test specifically includes: The prefabricated slurry in the negative pressure hole is extracted and filled with water, and the negative pressure hole is obtained after an interval of 2 to 4 hours; Providing a negative pressure environment to the negative pressure water injection hole, and observing the water output w per unit time of the negative pressure water injection hole; The obtained water output w is compared with the water output w1 required by the design. If w<w1, the grouting of the construction unit where the negative pressure hole is located is judged to be qualified. If w≥w1, the grouting of the construction unit where the negative pressure hole is located is judged to be unqualified.

7. The negative pressure grouting construction process for broken strata according to claim 6, characterized in that: The unqualified construction units are re-injected with slurry, and the prefabricated slurry is re-injected through the negative pressure holes and the grouting holes. After the re-injection of the construction units is completed, the above-mentioned negative pressure test operation is repeated until w<w1.

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