CN113309565B - Large-space large-inclination goaf curtain grouting method - Google Patents

Abstract

The patent relates to a large-space large-inclination goaf curtain grouting method, which comprises the following steps: laying a waterproof curtain investigation and exploration line between the surface river and the boundary of the mining area; on both sides of the waterproof curtain exploration line, the material feeding drill holes are constructed around the exploration drill holes in the exposed dead zone in an encrypted manner; and pouring cement-water glass double grout into the underground dead zone through the exploration drilling hole for revealing the dead zone, and pouring coarse aggregate quick-setting concrete into the underground dead zone through the feeding drilling hole. According to the invention, the curtain wall is constructed between the surface river and the boundary of the mining area to effectively cut off the supply of the surface river to the old goaf, so that the effective treatment of the large-space goaf and the coal rock stratum mining area with a larger inclination angle is realized.

Description

Large-space large-inclination goaf curtain grouting method

Technical Field

The patent belongs to the technical field of coal mine water disaster treatment, and particularly relates to a large-space large-inclination goaf curtain grouting method.

Background

Coal seams in mine areas in the northwest are generally buried shallow, and partial valley areas are exposed, so that most mining areas have long mining histories, but due to lack of planning in historical mining work and private excavation and random mining of some small coal kilns, all coal seams in the shallow part are mined to different degrees, and old dead areas with different sizes and shapes are formed. The old goafs located in the mountain torrents and river valleys generally have certain hydraulic connection with surface water, so that water burst can occur if the old goafs are exposed in the coal mining process, and the safety of coal mine production is threatened.

Grouting to block the goaf is the most common method at present. Due to the fact that old kiln underground dead zones are various in types, large in filling degree change, large in stratum inclination angle, variable in underground hydrodynamic conditions and the like, the diffusion range and the diffusion mode of slurry in a water guide channel and the underground dead zones are affected, if the old kiln underground dead zones are improperly controlled, the passive situation that the grouting amount is too large and the engineering cost is too high is caused, or a grouting weak area is formed due to insufficient grouting amount, the continuity of a water blocking curtain is poor, and the purpose of grouting blocking cannot be achieved.

In addition, in the goaf curtain grouting process, along with the continuous accumulation and rising of grouting bodies, accumulated water in the goaf outside the curtain body is more and more, and the water level is higher and higher. When the water level of the accumulated water is high and the water pressure is high, on one hand, the curtain body can be broken down by impact, on the other hand, the accumulated water can even break down the closed wall between the mine production system and the external goaf, once the closed wall is destroyed, a large amount of water in the high goaf can be instantly poured into the coal mine, and disastrous results are brought to the mine. The aggregate, the slurry and the grouting sequence and control are particularly critical because of the large space of the underground dead zone and the existence of adverse factors of large relief, large formation inclination angle and high underground water flow velocity in the dead zone. Conventional hard aggregates such as broken stones are put in, the hole diameter of the needed drill hole is large, the construction difficulty is increased, the drill hole is easy to lose along the trend of the stratum after the placement, and the drill hole is difficult to retain in the target area.

Disclosure of Invention

In view of the above analysis, the present invention aims to provide a curtain grouting method for a large-space large-inclination goaf, so as to solve the problem that the existing grouting method cannot realize curtain grouting plugging of the large-space large-inclination goaf.

The purpose of the invention is realized as follows:

a large-space large-inclination goaf curtain grouting method comprises the following steps:

laying a waterproof curtain investigation and exploration line between the surface river and the boundary of the mining area;

and (3) carrying out encrypted construction of feeding drill holes around the exploration drill holes of the uncovered area on two sides of the waterproof curtain exploration line, pouring cement-water glass double-slurry into the underground empty area through the exploration drill holes of the uncovered area, and pouring coarse aggregate quick-setting concrete into the underground empty area through the feeding drill holes.

Furthermore, the height of the goaf is more than or equal to 4m, and the inclination angle of the bottom plate of the goaf is 20-45 degrees.

Furthermore, a plurality of feeding lines are arranged in parallel to the waterproof curtain exploration line, feeding drill holes are constructed on the feeding lines at equal intervals, and the drill holes at the two ends of each feeding line do not expose the underground dead zone.

Furthermore, a first feeding line and a second feeding line are respectively arranged on two sides of the waterproof curtain investigation line, the vertical distance between the first feeding line and the waterproof curtain investigation line is 2m, and the feeding drilling density on the feeding lines is 4 m.

Furthermore, the old goaf bottom plate opposite to the first feeding drill hole has a first depth, the old goaf bottom plate opposite to the second feeding drill hole has a second depth, and the first depth is smaller than the second depth; during grouting, firstly, pouring coarse aggregate quick-setting concrete into the low dead zone through a second feeding drill hole to form a first curtain barrier; then, pouring coarse aggregate rapid-hardening concrete into the high empty area through the first feeding drill hole to form a second curtain barrier; and finally, pouring cement-water glass double grout under pressure in the exploration drilling hole between the first curtain barrier and the first curtain barrier.

Further, grouting the exploration drilling holes of the unexposed space area, and adding an accelerating agent accounting for 3% of the mass of cement into the grout; the grouting process from thin slurry to thick slurry is adopted, the water-cement ratio of the primary grouting concentration of the drill hole is 0.9:1-0.8:1, and the secondary grouting is 0.8:1-0.7: 1.

Further, in the pouring process of the coarse aggregate quick-setting concrete, the slump of the commercial concrete is reduced by adopting the polycarboxylic acid high-performance water reducing agent.

Further, in the pouring process of the coarse aggregate quick-setting concrete, the quick-setting admixture is added into the commercial concrete.

Further, adding an organic inert material or an aggregate material into the orifice when the commercial concrete is poured; and pouring concrete and organic inert material/aggregate material into the feeding drill holes in an intermittent staggered pouring mode.

Further, by adopting an intermittent commercial concrete pouring method, after the concrete of the previous batch is poured, the concrete of the next batch is poured after the initial setting for 1-4 hours, and the operation is repeated to finish the concrete pouring of all batches.

Further, the height of the coarse aggregate quick-setting concrete poured into the feeding drill hole 8 is 2-3m above the top plate of the goaf.

Further, the drilling process of exploring the borehole is: by using

And a 190mm roller bit is coreless drilled to the bedrock and then is put in

The wall protecting casing pipe is fixed with cement slurry, and the bedrock section is made of

The drill bit drills to 2.0m below the bottommost coal bottom plate and cores; the drilling process of the feeding drill hole comprises the following steps: by using

And a 245mm roller bit is coreless drilled to a bedrock and then is put in

The wall protecting casing pipe is fixed with cement slurry, and the bedrock section is made of

The drill bit drills to 2.0m below the goaf or the roadway floor and cores.

Further, after the waterproof curtain wall is constructed, the method further comprises the following steps:

and (5) carrying out construction rechecking and drilling to check the water plugging effect of the water-stopping curtain wall, and carrying out supplementary plugging on the position with the unsatisfactory water plugging effect.

Compared with the prior art, the invention can realize at least one of the following beneficial effects:

a) the curtain grouting method for the large-space large-inclination goaf adopts the construction sequence of arranging, sequencing and high-position construction at the lower part first, so that the construction effect of the curtain wall can be ensured, the effective treatment of the large-space goaf and the coal rock stratum mine area with a large inclination angle can be realized, and the construction cost can be reduced.

b) The invention provides a large-space large-inclination goaf curtain grouting method, which comprises the steps of surrounding exploratory drill holes for revealing roadways and goafs, respectively adding a row of feeding drill holes at two sides of an exploratory line, pouring coarse aggregate quick-setting concrete into the two rows of feeding drill holes, quickly stacking under the conditions of flowing water and large cross-sectional area through the feeding drill holes to quickly form coarse aggregate curtain barriers, pouring double grout into the exploratory drill holes for revealing the goafs on the exploratory exploration line between the two curtain barriers, compacting the coarse aggregate curtain barriers at two sides, controlling the diffusion range, filling gaps, improving the integrity of the curtain, realizing accurate grouting of the large-mining-height goafs and finally forming high-strength curtains.

c) According to the curtain grouting method for the large-space large-inclination goaf, provided by the invention, the aperture parameters of the curtain wall exploration drilling hole, the feeding drilling hole and the rechecking drilling hole are designed in a differentiated mode, and different grouting processes are adopted according to whether the goaf is exposed or not, so that the construction efficiency is improved while the blocking effect is ensured, and the construction cost is reduced.

Drawings

In order to more clearly illustrate the embodiments of the present specification or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments described in the embodiments of the present specification, and other drawings can be obtained by those skilled in the art according to the drawings.

FIG. 1 is a control flow chart of the large-space large-inclination goaf curtain grouting method of the present invention;

FIG. 2 is a schematic diagram of grouting control in the large-space large-inclination goaf curtain grouting method of the present invention;

FIG. 3 is a schematic plan view of the waterproof curtain inspection and exploration line and the feeding line of the present invention;

FIG. 4 is an enlarged plan view of the waterproof curtain investigation and exploration line and the two side feed lines of the present invention;

FIG. 5 is a schematic plan view of the temporary and permanent hydrological observation holes of the present invention;

fig. 6 is a sectional view of three rows of borehole grouting in the goaf with the bottom plate having a large inclination angle according to the present invention.

Reference numerals:

1-surface river; 2-mine area boundary; 3-water-rich abnormal area; 4-waterproof curtain investigation and exploration line; 5-a feeding line; 6-exploring and drilling the unexposed empty area; 7-exploratory drilling of the empty area is revealed; 8-feeding and drilling; 801-first charge drilling; 802-second charge drilling; 9-temporary hydrological observation holes; 10-permanent water observation Weekhole; 11-old empty area.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

Example 1

The invention discloses a method for grouting a curtain of a large-space large-inclination goaf, which comprises the following steps of:

laying a waterproof curtain investigation and exploration line between the surface river and the boundary of the mining area, wherein the waterproof curtain investigation and exploration line passes through an underground dead zone in the mining area to be treated;

and (3) carrying out encrypted construction of feeding drill holes around the exploration drill holes of the uncovered area on two sides of the waterproof curtain exploration line, pouring cement-water glass double-slurry into the underground empty area through the exploration drill holes of the uncovered area, and pouring coarse aggregate quick-setting concrete into the underground empty area through the feeding drill holes.

In this embodiment, the large-space large-inclination goaf means that the height of the goaf is more than or equal to 4m, and the inclination angle of a bottom plate of the goaf is 20-45 degrees.

In the embodiment, the spatial distribution characteristics of the underground dead zone and the water-rich abnormal zone 3 in the mining area to be treated are probed by a geophysical prospecting method. Specifically, a plurality of geophysical exploration lines (referred to as 'geophysical exploration lines' for short) are arranged at equal intervals in a mining area to be treated, and geological information of an underground dead zone of the mining area to be treated is probed, wherein the geological information of the underground dead zone comprises characteristics such as hydrogeological conditions, range and type of the underground dead zone, and the type of the underground dead zone comprises a goaf, a abandoned old roadway and a separation space formed among underground rock strata due to coal mining. The geophysical prospecting lines are located in an area defined by a river and a mine area boundary 2, the geophysical prospecting lines can be arranged approximately parallel to the flow direction of the river and are arranged along the flow direction of the river as a whole, a plane from the river to a mine area drainage point is defined as a physical prospecting area by combining relief, three geophysical prospecting lines are arranged in the area, the underground dead zone and the spatial distribution characteristics of the water-rich abnormal area 3 are identified according to a geophysical prospecting interpretation result, the water-rich abnormal area 3 comprises a water-rich abandoned old lane, a goaf and a separation space, and the water-rich abnormal area 3 is divided into a strong water-rich area and a weak water-rich area according to the water-rich degree.

In an optional implementation mode of the embodiment, the mine area to be treated is explored by a transient electromagnetic method and a high-density direct current method, and the distance between each exploration point is 10 m. By adopting an exploration mode combining a transient electromagnetic method and a high-density direct current method, different methods can be utilized for mutual verification and mutual supplement, so that the exploration precision is improved.

Based on the plane distribution of the dead zone and the water-rich abnormal zone 3 in the mining area to be treated, a waterproof curtain investigation line 4 is arranged between the surface river 1 and the boundary 2 of the mining area, and the waterproof curtain investigation line 4 penetrates through the dead zone and the water-rich abnormal zone 3 in the mining area to be treated.

After the coal seam is mined, mine water can be accumulated in a mine roadway or a mined-out area, inconsistent settlement deformation of all strata is caused by stress damage of overlying strata and original rock, a separation space is formed among underground strata, and a large amount of water resources of an overlying strata water-bearing layer are accumulated to the separation space and stored in the separation space under the action of negative pressure. Therefore, for the mining area adjacent to the river, the mining area water source is the separation layer water or mine water existing in the adjacent river and the empty area, and the water-rich abnormal area 3 comprises a water-rich abandoned old roadway, a goaf and a separation layer space. Thus, the waterproof curtain investigation survey line 4 is disposed between the surface river 1 and the mine site boundary 2 and is disposed as substantially parallel as possible to the main flow direction of the river, and may be disposed adjacent to the mine site boundary 2 if there is a mine site boundary restriction, as shown in fig. 3.

Optionally, the waterproof curtain investigation and exploration line 4 passes through the strong rich water area and the weak rich water area as much as possible under the condition of being as short as possible, and a curtain wall is formed by grouting in the later stage, wherein the curtain wall can fill and plug the strong rich water area and the weak rich water area, or the strong rich water area and the weak rich water area are divided into two parts, so that the number of water sources in the mine area and the water supply capacity of the water sources are reduced.

Optionally, the waterproof curtain investigation and exploration line 4 penetrates through narrow parts of a strong water-rich area and a weak water-rich area, so that the construction difficulty of grouting and plugging is reduced.

In an optional implementation mode of the embodiment, the feeding drill holes 8 are constructed around the exploration drill holes 7 of the exposed goaf in an encrypted mode, so that the spatial distribution range of the underground goaf is accurately explored, and the plane distribution range and the vertical development depth of the goaf are obtained. On the basis of the accurately determined underground dead zone range and the space characteristic parameters, on one hand, the grouting amount can be accurately estimated, resource waste and cost increase caused by excessive slurry are avoided, and the situation that the construction of a curtain wall is influenced due to insufficient slurry and a water passing channel cannot be effectively blocked can be avoided; on the other hand, grouting is carried out only by drilling holes in the determined underground dead zone range, and a stable and firm curtain wall with good barrier property can be accurately and quickly built in the underground dead zone through a plurality of grouting drilling holes, so that a water passing channel is effectively blocked.

Specifically, for the exploration drill holes 7 of the exposed dead zone on the waterproof curtain exploration line 4, at least one row of feeding drill holes 8 are arranged on two sides of the exploration drill holes 7 of the exposed dead zone on the waterproof curtain exploration line, each added row of feeding drill holes 8 is arranged in parallel to the waterproof curtain exploration line, the density of the feeding drill holes 8 in the same row is 4m, and the vertical distance between every two adjacent rows of feeding drill holes 8 is 2 m. When the drill hole drill meets the coal seam or the unexposed dead zone, the encrypted drill hole is stopped to continue construction, the boundary of the dead zone is positioned between the encrypted drill hole of the unexposed dead zone and the encrypted drill hole of the adjacent uncovered dead zone, and the drill holes are gradually encrypted until the range of the underground dead zone is accurately determined, so that the range of the water channel is accurately defined, and the method has important significance for improving the construction efficiency of the curtain wall, the separation effect of the curtain wall and accurately controlling the grouting amount by accurately probing the boundary of the underground dead zone, particularly the boundary of the water-rich zone.

Through throwing 8 slip casting of material drilling to multirow encryption, can accomplish dead zone slip casting shutoff water channel fast, and promote the water proof performance of waterproof curtain wall, nevertheless consider construction cost and time, if all reveal in the drilling in dead zone all slip casting, then meet when the space on a large scale, the thick liquid volume of needs is very big, lead to with high costs, consequently under the water proof effect prerequisite of assurance water curtain wall, the drilling quantity of minimize slip casting, it is vital to reduce cost and improvement efficiency of construction. In an alternative embodiment of this embodiment, as shown in fig. 4 to 6, a row of waterproof curtain investigation charge drill holes 8 are respectively arranged in parallel on two sides of a drill hole of a waterproof curtain investigation survey line 4 where a dead zone has been exposed, the row of charge drill holes 8 form charge lines 5, the waterproof curtain investigation survey line 4 has a vertical distance of 2m from the charge lines 5 on two sides thereof, that is, the waterproof curtain investigation survey line 4 is used as a reference line and located in the middle, a first charge line and a second charge line are respectively arranged in parallel on two sides thereof, the vertical distances between the first charge line, the second charge line and the waterproof curtain investigation survey line 4 are 2m, and the hole sites are arranged in a quincunx shape.

According to the mine curtain grouting specification (DZ/T0285-2015), the thickness of the curtain for grouting the non-soluble rock stratum is not less than 5 m. Because the infiltration scope of thick liquid in the rock mass is about 1m, through setting up a waterproof curtain investigation survey line 4, two encrypted throwing material lines 5, and the interval of two throwing material lines 5 apart from the investigation survey line is 2m, can make the slip casting scope be greater than 6m, also the curtain thickness of this embodiment can reach more than 6m, satisfies the minimum separation thickness requirement of the waterproof curtain wall of separation requirement.

In an optional implementation manner of this embodiment, after the waterproof curtain wall is constructed, the waterproof curtain wall is solidified for a period of time to form a stable waterproof curtain wall, the rechecking drill holes are constructed in the region range between the grouting drill holes in the dead zone range, and the grouting effect is checked according to the core condition taken out by the rechecking drill holes, so that the checking of the water blocking effect of the waterproof curtain wall is realized. And observing the taken out rock core, and mainly observing the relation between the concrete wall and the top wall of the dead zone. If the concrete top plate and the top wall of the dead zone are jointed into a whole, the water passing channel is successfully plugged by the curtain wall; if not laminating between concrete roof and the dead zone roof, the shape of the two terminal surface is different, shows that there is the space between concrete roof and the dead zone roof, and water channel is not the shutoff completely, carries out the shutoff of thick liquid mending once more of slip casting through the inspection hole to guarantee the shutoff separation effect of curtain wall.

In one optional embodiment, the single cement slurry is adopted for grouting plugging, so that the single cement slurry can be fully diffused in a curtain grouting weak area, and the strength and the anti-permeability performance of a curtain body are enhanced.

For goaf curtain grouting with large space and large inclination angle, the grouting process is further improved as follows in the embodiment: the method has the advantages that the aperture parameters of the exploration drilling, the feeding drilling 8 and the rechecking drilling of the curtain wall are designed in a differentiated mode, different grouting processes are adopted according to whether the goaf is exposed or not, the construction efficiency is improved while the blocking effect is guaranteed, the construction cost is reduced, and the flood control problem of the goaf with the goaf height being more than or equal to 4m and the goaf bottom plate inclination angle being 20-45 degrees is solved.

In this embodiment, the following differential design is performed on the aperture parameters and the construction process of the exploration drilling, the feeding drilling 8 and the rechecking drilling, specifically as follows:

(1) exploratory drilling using

And a 190mm roller bit is coreless drilled to the bedrock and then is put in

The wall protecting casing pipe is fixed with cement slurry, and the bedrock section is made of

The drill bit drills to 2.0m below the bottommost coal bed plate and cores.

(2) The material feeding and drilling 8 adopts

And a 245mm roller bit is coreless drilled to a bedrock and then is put in

The wall protecting casing pipe is fixed with cement slurry, and the bedrock section is made of

The drill bit drills to 2.0m below the goaf or the roadway floor and cores.

(3) Rechecking the borehole

And a 190mm roller bit is coreless drilled to the bedrock and then is put in

The wall protecting casing pipe is fixed with cement slurry, and the bedrock section is made of

The drill bit was drilled 1.0m below the top plate of the cast-in concrete and cored.

Considering that the water supply condition of a plurality of layers of goafs and complex media is unknown, the method aims to prevent slurry from diffusing to cause high construction cost and difficult rapid solidification into a stable and effective water-blocking curtain wall. In this embodiment, when the curtain body is constructed, the feeding drill hole 8 on the feeding line 5 is filled with coarse aggregate quick-setting concrete, and commercial concrete is selected to fill the goaf according to the design requirement, wherein the strength grade is C30, and the grading is as follows: first grading (5-20mm, maximum particle size 20 mm); the exploration drilling hole 7 of the exposed dead zone on the exploration line is filled with cement-water glass double-slurry, the cement-water glass double-slurry and the cement single-slurry are used in a matching way to serve as grouting materials, the double-slurry has short and controllable gelling time, has certain anti-scouring capability and is a main grouting material; the cement single liquid slurry has good diffusivity, high gel strength and good combination with rock and soil mass, and is a supplementary grouting material.

For exploration drilling holes of exposed roadways and goafs, a row of feeding drilling holes are added at equal intervals of 2m on two sides of an exploration line within the range of the exposed goaf, the range of the explored goaf is detailed, coarse aggregate quick-setting concrete is poured into the two rows of feeding drilling holes to quickly form coarse aggregate curtain barriers, then double grout is poured into the exploration drilling holes 7 of the exposed goaf on the exploration line between the two curtain barriers, the coarse aggregate curtain barriers on two sides are compacted, and finally a high-strength curtain is formed. If a goaf is explored, a material throwing line is arranged on the same side of the exploration line, the length of the material throwing line is far smaller than that of the exploration line, and the material throwing line crosses the goaf; if a plurality of goafs are explored, a plurality of disconnected feeding lines are arranged on the same side of the exploration line, so that the drilling construction quantity is reduced, the cost is reduced, and the construction period is shortened.

Further, for the exploration drilling hole 6 of the empty area not exposed on the exploration line, double-slurry grouting is carried out to fill the rock mass cracks, double-slurry can be fully diffused and filled along the cracks or weak areas in the solid coal rock layer, the anti-permeability performance is enhanced, and therefore the integral blocking and anti-permeability performance of the curtain wall is further improved.

Considering that the underground dead zone has large relief, large stratum inclination angle and fast underground water flow velocity, the material is easy to be lost along the stratum tendency after being thrown, and the target zone is difficult to be retained. The bottom plates of different empty areas and even the same empty area have relief, the depths of the bottom plates of the empty areas are different, the deeper the bottom plate of the empty area is, the lower the position of the empty area is, the smaller the depth of the bottom plate of the empty area is, the higher the position of the empty area is, and the slurry tends to flow from a high position to a low position.

In an optional implementation manner of the embodiment, for a coal rock stratum with a large inclination angle, such as a coal rock stratum with an inclination angle of about 20-45 degrees, in order to ensure that the treatment effect of an old roadway or a goaf is revealed, a construction sequence of arranging, sequencing, firstly from a lower position to a higher position is adopted to ensure the construction effect of the curtain wall, and the construction cost can be reduced at the same time. Specifically, as shown in fig. 6, the bottom plate of the gob 11 is inclined at a large inclination angle, the bottom plate of the gob 11 directly opposite to the first feeding drill hole 801 has a first depth, the bottom plate of the gob 11 directly opposite to the second feeding drill hole 802 has a second depth, the first depth is smaller than the second depth, the first feeding drill hole 801 corresponds to an upper gob, and the second feeding drill hole 802 corresponds to a lower gob. During grouting, firstly, pouring coarse aggregate quick-setting concrete into the low dead zone through the second feeding drill hole 802, and forming a retaining wall, namely a first curtain barrier body after the pressure of a final hole is stable so as to prevent the slurry from being diffused in a large range; then, coarse aggregate quick-setting concrete is poured into the high-place dead zone through the first feeding drill hole 801, after the pressure of a final hole is stable, another retaining wall is formed, namely a second curtain barrier is formed, after the concrete poured into the high-place dead zone and the low-place dead zone form the curtain barriers with certain strength, double grout is poured into the exploration drill hole 7 between the two curtain barriers, the curtain bodies on the two sides are compacted, and finally a compact and high-strength underground impermeable curtain is formed.

Further, a grouting sequence is determined according to the flowing direction of water flow between the first feeding drill hole 801 and the second feeding drill hole 802, and illustratively, according to hydrologic monitoring information, it is determined that the first feeding drill hole 801 is located at the upstream of the second feeding drill hole 802, coarse aggregate quick-setting concrete is poured into the downstream second feeding drill hole 802 first, then coarse aggregate quick-setting concrete is poured into the upstream first feeding drill hole 801, finally, double grout is poured into the exploratory drill hole 7 between the two curtain barriers, and the curtain barriers on the two sides are compacted. According to the grouting sequence, the barrier is formed at the downstream, so that the loss of slurry during upstream grouting can be prevented, and the curtain barrier can be formed quickly.

In the embodiment, the selection of the grouting material is 42.5 silicate cement slurry, and the water-cement ratio is 0.8:1-0.6: 1. When double-slurry grouting is adopted, an accelerator (water glass) accounting for 3% of the mass of cement is added into the slurry; when the underground empty area is filled by adopting coarse aggregate concrete through a feeding drill hole or an exploratory drill hole 7 for revealing the empty area, commercial concrete is selected to fill the empty area, the concrete is formed by mixing cement, fine sand and stones, and in order to increase the water plugging effect, water glass is added, and the strength grade of the concrete is C30. In the aspects of grouting pressure and duration, the final pressure of drilling and grouting is not lower than 2MPa, the duration is not lower than 10 minutes, and fine adjustment can be performed according to specific situations on site.

In this embodiment, the following curtain grouting process is adopted for the exploration drilling 6 of the unexposed space:

and (3) filling grouting into the solid rock mass by adopting an orifice-closed pure pressure type grouting method for the exploration drilling holes 6 in the unexposed vacant area, and strictly controlling grouting flow and injection rate according to the development condition of the cracks of the stratum holes. Illustratively, in the section where the stratum is largely leaked and the fracture is relatively developed, the injection rate is 100-200L/min; for general areas and areas where cracks do not develop, the injection rate is 50-150L/min. For the purpose of accelerating construction, after the pressure is increased, the injection rate of 50-150L/min is used to reach the designed final pressure condition. The grouting pressure is determined according to the design requirement, and the pressure of the orifice grout inlet pipe is controlled in the construction process. And respectively controlling grouting pressure when grouting is carried out in series holes or in parallel holes.

In the grouting process, an accelerating agent such as water glass accounting for 3% of the mass of cement is added into the grout for grouting the cracks of the solid holes, so that the grout injected into the cracks is solidified as soon as possible to form a curtain and prevent the grout from losing along the water flow direction of the cracks. During grouting, a grouting process from thin slurry to thick slurry is adopted, specifically, the water-cement ratio of the primary grouting concentration of the drill hole is 0.9:1-0.8:1, and the secondary grouting is 0.8:1-0.7: 1.

If the grouting amount exceeds the designed grouting amount in the grouting process, the pressure of the orifice still does not rise, and an intermittent grouting process is adopted, and the intermittent time is controlled to be about 10-12 hours. And after the interval, the grouting is continued, and a grouting process of starting from thin slurry and then gradually thickening is still adopted, wherein the secondary grouting is about 50% of the design amount until the pressure of the orifice is increased and reaches the preset pressure. And (4) performing intermittent grouting, pouring clear water after stopping grouting, completely emptying the cement slurry in the grouting pipe, wherein the amount of the poured clear water is about 3 times of the sum of the capacities of the grouting pipe and the hole.

In one optional embodiment, for exploration drilling holes of a goaf which is not exposed, a stage differential pressure type grouting process is adopted, in the first grouting stage, grouting is carried out for 1 minute at the grouting pressure of 8-10Mpa, the grouting pressure is high, and the spread of original fractures in a rock stratum can be expanded properly; and then, in a second grouting stage, grouting is carried out for more than 10 minutes at the grouting pressure of 2-4Mpa, and the final pressure of the drilling grouting is 2 MP. The original crack in the reservoir can be expanded through the large-pressure grouting in the first stage, then the grouting is carried out immediately, the expanded crack is filled, the grouting permeation range can be expanded, the rock mass in a larger range is solidified into a whole by grout, and therefore the stability of the waterproof curtain wall is improved.

In this embodiment, the process of filling the underground dead zone with coarse aggregate quick-setting concrete (hereinafter may be referred to as "concrete") specifically includes the following steps:

for a goaf with a large stratum inclination angle (20-45 degrees), after commercial concrete enters the goaf through a ground vertical drilling hole, the commercial concrete falling to the ground flows towards the deep direction, and if no measures are adopted, the grouting amount of coarse aggregate quick-setting concrete is possibly large, so that the ineffective diffusion control measures of the commercial concrete must be adopted. Adopts commercial concrete pouring control technology. The treatment method of the embodiment adopts the following commercial concrete pouring technology and commercial concrete pouring control technology to carry out feeding and grouting on the underground dead zone, and specifically comprises the following steps:

firstly, in the pouring process of coarse aggregate quick-setting concrete, a polycarboxylic acid high-performance water reducing agent is adopted to reduce slump of commercial concrete.

The slump of the coarse aggregate quick-setting concrete indicates the strength and weakness of the fluidity of the concrete, and the larger the slump, the larger the fluidity, and vice versa. The slump of the coarse aggregate quick-setting concrete is slightly larger when the coarse aggregate quick-setting concrete is poured, so that the phenomenon of hole blocking of the coarse aggregate quick-setting concrete is avoided, the slump is reduced by adopting the polycarboxylic acid high-performance water reducing agent on site along with the concrete pouring, and the slump of the concrete is gradually reduced until the slump is reduced to the lowest pourable value.

Secondly, the quick-setting admixture is added into the commercial concrete to accelerate the concrete solidification.

After the accelerator is added into the commercial concrete, the setting time of the commercial concrete is shortened, so that ineffective diffusion can be controlled by adding the accelerator. The additive is directly added from an orifice on a construction site, and can also be added into a concrete pump truck on the site to be uniformly stirred and then poured into a drill hole. The on-site accelerator is water glass, which belongs to a non-segregation concrete additive material and has good performance effect.

And thirdly, adding an organic inert material or an aggregate material into the orifice when the commercial concrete is poured so as to reduce the fluidity of the concrete.

In order to reduce the ineffective diffusion of concrete, organic inert materials such as sawdust and the like can be synchronously added when the concrete is poured into a drilled hole, one or more of aggregates such as fly ash, sand or rice stone can also be synchronously added, the added materials can reduce the fluidity of the concrete, and the materials can replace the concrete to fill the space of a goaf.

Stagger pouring commercial concrete or other materials

When the commercial concrete is poured, if other materials are synchronously added, the holes are easy to block, so that the concrete and the organic inert material/aggregate material can be poured into the feeding drill holes in an intermittent staggered pouring mode. That is, after a certain volume of concrete is poured, filling materials such as fly ash, sand, loess and sawdust are then poured, and the fluidity of the concrete in the goaf is reduced by staggering the filling materials at intervals.

Adopting intermittent commercial concrete pouring method

After the last batch of concrete is poured, the pouring can be stopped, the concrete poured into the goaf has certain strength after being primarily solidified for about 1-4h, the fluidity of the concrete is deteriorated, and then the next batch of concrete is poured. Then waiting for a period of time, pouring concrete of the subsequent batch, and repeating the operations to finish the concrete pouring of all batches. By adopting the intermittent filling method, the filling amount and the equal setting time of each batch of concrete can be determined according to the situation, and the interval is at least 12 hours generally.

Combination control method

The technical measures in the first to the fifth aggregate pouring control measures can be combined for use, for example, when the slump of concrete is reduced, other grouting materials can be added into a drilled hole, and then an intermittent grouting method is adopted.

Method for filling multiple holes

In the method, a plurality of drill holes can be simultaneously filled, concrete, water glass, fly ash, sand and the like are respectively filled, and the filled grouting materials are mixed in the goaf, so that the free diffusion of the concrete can be effectively reduced.

Method for pouring in divided holes

The commercial concrete control measures are concentrated on a grouting and pouring mode, if the control effect is not obvious and the pouring amount is still large, a hole dividing control measure is adopted, specifically, a row of feeding drill holes are additionally arranged at the downstream of the goaf, large granular gravel materials (the grain diameter is 15-20mm) with the blocking effect are specially poured, and the other upstream drill holes are poured according to the method, such as pouring coarse aggregate quick-setting concrete.

Before pouring, an accelerating agent (water glass) accounting for 3% of the mass of the cement is added into the concrete aggregate, so that the concrete aggregate injected into the goaf is solidified as soon as possible, and the slump of the concrete is controlled to be between 150mm +/-30 mm. And (3) adopting an intermittent concrete pouring process, probing the stacking height of the concrete before the next pouring, and making a record. During grouting, the grouting speed of concrete and the phenomenon of blockage in the pipe are observed, and various phenomena in the grouting process are recorded. And finally, the height of the coarse aggregate quick-setting concrete poured into the feeding drill hole 8 is 2-3m above the top plate of the goaf, and a double-slurry pressurized pouring process is adopted in the hole section of the upper drill hole.

Compared with the prior art, the large-space large-inclination goaf curtain grouting method provided by the embodiment has at least one of the following beneficial effects:

1. by adopting the water inrush channel exploration and treatment integrated technology, all water inrush channels are not required to be searched deliberately, and the underground water-stop curtain is directly constructed between the surface river and the boundary of the mining area so as to replace the investigation and search and treat the integrated construction, thereby greatly saving the engineering cost and solving the problems that the geological information of the underground dead zone is difficult to accurately obtain, the grouting process is difficult to control and the threat of water accumulation outside the grouting curtain of the goaf is large.

2. By adopting the construction sequence of arranging, sequencing and descending at first and then ascending at second, the construction effect of the curtain wall can be ensured, the effective treatment of a large-space goaf and a coal rock stratum mine area with a larger inclination angle can be realized, and the construction cost can be reduced.

3. Around exploratory drilling holes for exposing a roadway and a goaf, a row of feeding drilling holes are respectively added on two sides of an exploratory line, coarse aggregate quick-setting concrete is poured into the two rows of feeding drilling holes, the feeding drilling holes can be quickly stacked under the conditions of flowing water and large cross-sectional area of water to quickly form coarse aggregate curtain barriers, then double grout is poured into the exploratory drilling holes for exposing the goaf on an exploratory exploration line between the two curtain barriers, the coarse aggregate curtain barriers on the two sides are compacted, the gap filling effect is realized while the diffusion range is controlled, the integrity of the curtain is improved, the accurate grouting of the goaf with large mining height can be realized, and finally the high-strength curtain is formed.

4. The method has the advantages that the aperture parameters of the curtain wall exploration drilling, the feeding drilling and the rechecking drilling are designed in a differentiated mode, different grouting processes are adopted according to whether the empty area is exposed or not, the blocking effect is guaranteed, meanwhile, the construction efficiency is improved, and the construction cost is reduced.

5. Determining a grouting sequence according to the flow direction of water flow between feeding drill holes on two sides of the curtain exploration line, firstly pouring coarse aggregate quick-setting concrete into the feeding drill holes on the downstream, then pouring coarse aggregate quick-setting concrete into the feeding drill holes on the upstream, and finally pouring double grout into the exploration drill holes between the two curtain barriers to compact the curtain bodies on the two sides. According to the grouting sequence, the barrier is formed at the downstream, so that the loss of slurry during upstream grouting can be prevented, and the curtain barrier can be formed quickly.

Example 2

The invention further discloses a large-space large-inclination goaf curtain grouting method which is improved on the basis of the embodiment 1, specifically, a hydrological tracing test is carried out before grouting is carried out in the exploration drilling hole 7 of the uncovered goaf, a key blocked water channel is accurately determined based on the hydrological tracing test, and the required mud amount is estimated.

Before grouting the exploration drilling hole 7 of the exposed empty area, when the planned grouting water plugging curtain exploration drilling hole is explored to the old air or the old roadway, one or more feeding drill holes 8 are selected from the encrypted feeding drill holes 8 as temporary hydrological observation holes 9, after the monitoring task is completed, the temporary hydrological observation hole 9 and other feeding drill holes 8 are subjected to feeding and grouting plugging, a permanent hydrological observation hole 10 is constructed on the outer side of the encrypted feeding line 5, the hole depth of the permanent hydrological observation hole 10 is the current exploration depth, the grouting plugging is not carried out on the permanent hydrological observation hole, after the construction of the water curtain wall is finished, the water curtain wall is still used for hydrologic monitoring, specifically, the enclosing and blocking effect of the curtain wall is judged by a pressure water injection test in the later stage, after the temporary hydrological observation hole 9 is plugged and the curtain wall is cured and stabilized, the permanent hydrological observation hole 10 is used for carrying out the tracer test again to evaluate the seepage-proofing performance and the obstructing effect of the waterproof curtain.

Specifically, a tracer which is good in stability and does not pollute underground water is put into an exploration hole to eliminate pollution to the underground water, water samples are taken at the same time in a temporary observation hole and a permanent observation hole, the concentration of the tracer is measured, a concentration contour map is drawn, the using amount of plugging slurry can be determined according to the concentration change difference value of two sides, and if the concentration change difference value of the tracer is large, the width of a water channel is small, and the space of an underground dead zone is small; if the concentration change difference of the tracer is small, the width of the water channel is large, the space of the underground vacant area is large, and more plugging slurry is needed. The selected tracer has the characteristics of no pollution to underground water and soil, easy field identification or detection, stable existence in water, no chemical reaction of various tracers, easy acquisition of raw materials and the like.

In an alternative embodiment, the rule for determining the amount of plugging mud is: the sum of the mud fully injected into the exploration drilling hole and the mud permeation quantity is the standard grouting quantity V of a single drilling hole; if the concentration of the tracer is reduced within 30%, the required mud dosage is 3-4V; if the concentration of the tracer is reduced by 30-60%, the required mud dosage is 2-3V; if the concentration of the tracer agent is reduced by 60-80%, the required mud dosage is 1.2-2V; if the concentration of the tracer is reduced by more than 80%, the required mud dosage is 1-1.2V. By accurately calculating the amount of the slurry, the problem that the enclosing effect of the curtain wall is influenced due to insufficient slurry and the problem that the slurry is too much to cause resource waste are avoided, so that the success rate of the curtain wall is ensured, and the cost is obviously reduced.

In the exploration hole construction process, water samples are collected in layers, and water level information is monitored. And (3) carrying out indoor chemical component analysis on the collected water sample, comparing the water sample with the water quality of a river, and determining possible water sources of each aquifer by adopting a fuzzy recognition method so as to further accurately define a water passage. Based on the found water sources of all aquifers and the defined water passing channels, layered treatment and layered construction are pertinently carried out.

In an optional implementation manner of the embodiment, the underground dead zone range is judged based on the water level change condition in the temporary hydrologic monitoring hole. Specifically, for the drill hole with the continuous core and good integrity, the water level change condition is observed through an in-hole water injection method so as to judge the underground dead zone range. If the water injection volume is in direct proportion to the water level in the hole and the water level rises quickly, the range of the empty area is judged to be small, and quick-setting cement grout is adopted for grouting and plugging to continue drilling downwards to the designed depth after strength is formed.

And stopping drilling and starting the feeding drill hole 8 for construction for the drill hole with broken core, dropped drill and large loss of slurry. At the moment, a part of exploration drill holes are selected from the exploration drill holes to carry out a water pumping test, a part of feeding drill holes 8 are selected to serve as temporary hydrological observation holes 9, and feeding grouting is carried out at the later stage. And measuring and calculating hydraulic parameters according to the relation between the water pumping quantity and the water level descending, wherein the water level of the two temporary hydrological observation holes 9 is rapidly descended along with the increase of the water pumping volume, so that the situation that the water source supply of the underground dead zone is less, and limited water storage units such as a mining subsidence area or a waste roadway are suspected can be judged. Along with the increase of the pumping volume, the water levels of the two temporary hydrological observation holes 9 are basically stable, and the condition that the water source supply in the underground dead zone is sufficient can be judged. Further, a permanent hydrological observation hole 10 is constructed on the outer side of the encrypted feeding line 5, the outer side of the feeding line 5 refers to one side of the feeding line 5 far away from the direction of the waterproof curtain investigation survey line 4, after the feeding of a feeding drill hole 8 is formed in the ground to form a curtain wall, the permanent hydrological observation hole 10 is located on two sides of the curtain wall, as shown in fig. 5, the hole depth of the permanent hydrological monitoring hole is the current investigation depth, multiple groups of observation data assist in determining a section needing important treatment, coarse aggregate is fed into the feeding drill holes 8 on two sides to quickly construct an underwater temporary coarse aggregate curtain barrier, then C35 quick-setting concrete is injected into the feeding drill hole under pressure to form a strong and stable coarse aggregate curtain barrier, a water pumping test is carried out on the central exploratory drill hole, the lowering change of the permanent hydrological observation hole 10 is observed at the same time, and if no change exists, the plugging effect is better, the construction can be continued. And injecting water glass-cement slurry into the exploratory drill hole under pressure to squeeze the coarse aggregate curtain barriers at the two sides tightly. And after solidification, drilling construction is continued until the designed hole depth is reached. The construction scheme integrates exploration feeding and treatment, is favorable for accelerating the construction progress and greatly shortens the construction period.

When the seepage-proofing capability of the waterproof curtain is checked in the later stage, the permanent hydrological observation hole 10 can still play a role, and the permanent hydrological observation hole 10 is protected from being damaged in the construction process.

Compared with the prior art, according to the curtain grouting method for the large-space large-inclination goaf, a part of drilled holes are selected as hydrological temporary monitoring holes when the planned grouting water plugging curtain exploration drilled holes are explored to the old sky or the old roadway before grouting, simple single-hole, group-hole or multi-hole water pressing and injecting tests are adopted to obtain underground water level changes of different places during grouting and after grouting engineering is completed, grouting water plugging effects are analyzed according to underground water level changes, and design and construction of key grouting hole groups are guided. And meanwhile, the monitoring hole monitors the slurry diffusion range in the grouting process fed back in real time, and the grouting parameters are adjusted through the fed back slurry diffusion range information to control the slurry diffusion range. During the implementation of grouting engineering, the comprehensive grouting effect monitoring work combining drilling and hydrogeological tests is carried out, the grouting effect and the dynamic evolution characteristics of a reinforced area are mastered in time, and the informatization adjustment of grouting design is guided.

Example 3

Because the suitable construction time of the high-altitude area is only 4-5 months per year, the suitable construction time is very short, the traditional mode of exploring first and treating second is adopted, all water passing channels need to be searched first, then the underground waterproof curtain wall is built, the exploration and the building of the underground waterproof curtain wall cannot be completed within two months, and the curtain wall building cannot be completed within a suitable construction period.

Based on the above problems, another specific embodiment of the present invention discloses a method for grouting a curtain in a large-space large-inclination goaf based on embodiments 1 and 2, wherein exploration drilling construction is performed according to a laid waterproof curtain exploration survey line 4, during the construction process of exploration drilling on the waterproof curtain exploration survey line 4, grouting and plugging are performed in an exploration drilling 7 in an exposed goaf to form a curtain wall grouting section, and the curtain wall grouting section on the waterproof curtain exploration survey line 4 and an adjacent solid ground layer section together form a waterproof curtain wall. Through the construction mode of construction and grouting at the same time, the construction progress is remarkably accelerated, and the construction period is shortened.

And (3) carrying out exploration drilling construction according to the laid waterproof curtain exploration and control exploration line 4, wherein the exploration drilling is used for accurately exploring the hydrogeological conditions, the range and the type (goaf or abandoned old roadway) of the underground goaf so as to determine the positions, the filling degree and the water accumulation condition of the underground goaf and the abandoned old roadway. And determining the voidage of the underground empty area according to the probing result, and estimating the type and the amount of the slurry (filling material) according to the voidage of the underground empty area.

Judging whether the exploration drilling hole is drilled in the goaf or not according to the adopted core, recording the exploration drilling hole in the uncovered goaf and the exploration drilling hole 6 in the uncovered goaf, grouting and plugging the exploration drilling hole 7 in the uncovered goaf in the exploration drilling construction process, plugging a water passing channel in the underground goaf after grout is injected into the goaf, and forming a curtain wall grouting section and an adjacent solid stratum section to form a water-stop curtain wall together.

Because the exploration drilling hole of the uncovered dead zone, the underground rock body of the drilling hole is an entity, the entity rock stratum has a good water-resisting effect, and grouting is not needed in a certain range of the exploration drilling hole of the uncovered dead zone, so that the construction cost can be saved. However, considering that the underground solid stratum section, especially the crack which can develop under the influence of coal mining, has leakage, so in order to improve the water-resisting performance of the waterproof curtain wall, in an optional embodiment, the exploration drilling hole 6 of the uncovered dead zone is grouted, the rock crack which develops on the underground solid stratum section on the waterproof curtain exploration line 4 is filled, and the rock crack which develops on the solid stratum section is filled, so that the blocking effect of the solid stratum section can be further enhanced, and the water-resisting performance of the waterproof curtain wall is ensured.

In the actual construction process, because the drilling hole intervals are small and are easy to influence each other, and certain strength increasing time is needed for feeding aggregate, a construction team is divided into a plurality of operation groups, the operation groups are named as an exploration one class, an exploration two classes, a feeding one class, a feeding two classes, a hydrological observation class and the like, the waterproof curtain investigation and exploration line 4 is subjected to subsection construction and hole jump construction, and the distance between two adjacent construction drilling machines is ensured to be more than 5m so as to avoid mutual influence. By adopting the construction mode of segmentation and hole jumping, the construction efficiency is improved, and the construction difficulty is reduced.

In an optional implementation manner of this embodiment, the waterproof curtain investigation and exploration line 4 is divided into 2-4 sections for segmental construction, and meanwhile, the groundwater seepage path is considered, and during the segmental construction, each construction section starts to be constructed from the upstream and finishes folding to the downstream.

Illustratively, the waterproof curtain investigation survey line 4 is divided into two sections, a first section of the survey line is drilled from upstream to downstream in a survey, then the second section of the survey line is drilled, after the first section of the survey line is drilled in the survey, the underground dead zone condition of the open area of the open hole in the first section of the survey line is counted and recorded, the encrypted drilling construction is carried out in the range of the open area in the first section of the survey line in the survey in the second shift, and meanwhile, the encrypted feeding drilling hole 8 of the open area in the first section of the survey line is grouted from upstream to downstream in the first shift to form a first curtain wall section. After the encrypted drilling construction of the exposed dead zone range on the first section of the exploration line is completed in the second exploration line, the encrypted feeding drilling 8 construction is carried out in the exposed dead zone range on the second section of the exploration line. After the grouting construction of all grouting drill holes on the first section of exploration line is completed in one feeding process or in the grouting construction process, grouting is performed in the exploratory drill holes 7 (containing the encrypted feeding drill holes 8) with the exposed dead zones on the second section of exploration line from upstream to downstream in two feeding processes until the grouting of all the exposed dead zones on the second section of exploration line is completed, and a second curtain wall grouting section is formed, wherein the first curtain wall grouting section and the second curtain wall grouting section both comprise solid ground intervals and wall body sections formed by solidifying slurry, and the first curtain wall grouting section and the second curtain wall grouting section jointly form a whole waterproof curtain wall. By adopting the sectional construction mode, the construction efficiency is greatly improved, and the construction period is shortened.

In this embodiment, the waterproof curtain investigation line 4 may be a straight line or a broken line, and the feeding lines 5 encrypted in parallel with the waterproof curtain investigation line 4 are not particularly parallel to two straight lines in a strict geometric sense, and the waterproof curtain investigation line 4 and the two feeding lines 5 may be substantially parallel to each other, so that the drill holes at two end points of the investigation line are removed, and two adjacent investigation lines do not intersect with each other.

In an optional implementation manner of this embodiment, after the waterproof curtain wall is constructed, the water blocking effect of the waterproof curtain wall is checked, and the positions with the undesirable water blocking effect are subjected to supplementary blocking.

Illustratively, the water plugging effect of the curtain wall is evaluated by comparing the water inflow amount of the mine before and after construction, and the water plugging effect of the curtain wall is evaluated according to the water inflow amount data of the mine before and after construction. Specifically, the hydrological observation hole water level data on two sides of the curtain body are observed every day, and a water pumping test can be carried out to verify whether hydraulic connection exists between water-containing layers on two sides of the curtain body or not and whether local or large-area streaming exists or not when necessary. And observing the water inflow amount of a mine drainage point at regular time, comparing the change condition of the water inflow amount with time in the same period of time in the last three years, and analyzing the water interception rate and the water stopping effect of the curtain body. Furthermore, the groundwater level of the river opposite to the bank is observed, the groundwater flow direction before and after construction is analyzed, the flow field distribution condition of groundwater cannot be influenced by the existence of the curtain body, the new flow field distribution rule is demonstrated, the water inflow of a mine is predicted, and an area which is important to carry out hydrological monitoring is defined. Furthermore, the stability and the impermeability of the curtain body can be analyzed by combining numerical modeling with actual hydrogeological condition parameters, and the water plugging effect of the curtain wall can be evaluated in an auxiliary manner.

Compared with the prior art, the curtain grouting method for the large-space large-inclination goaf has the advantages that in the construction process of exploring a drill hole on the waterproof curtain exploration line, grouting plugging is carried out in the explored drill hole of the exposed goaf, construction progress is remarkably accelerated through the construction mode of construction and grouting at the same time, and the construction period is shortened.

The above-mentioned embodiments, objects, technical solutions and advantages of the present application are described in further detail, it should be understood that the above-mentioned embodiments are merely exemplary embodiments of the present application, and are not intended to limit the scope of the present application, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present application should be included in the scope of the present application.

Claims (5)

1. A large-space large-inclination goaf curtain grouting method is characterized by comprising the following steps:

laying a waterproof curtain investigation and exploration line between the surface river and the boundary of the mining area;

on two sides of the waterproof curtain exploration line, carrying out encrypted construction on the exploration drilling holes around the exposed dead zone, and feeding and drilling the holes;

pouring cement-water glass double grout into the underground dead zone through the exploration drilling hole of the exposed dead zone, and pouring coarse aggregate quick-setting concrete into the underground dead zone through the feeding drilling hole;

wherein the height of the large-space large-inclination goaf is more than or equal to 4m, and the inclination angle of the bottom plate is 20-45 degrees; the drilling process for exploring a borehole is as follows: adopting phi 152 mm and phi 190mm roller bit to drill coreless into bedrock, then setting phi 127 mm protective wall casing pipe and fixing pipe with cement slurry, drilling the bedrock section to 2.0m below the coal bottom plate of the bottommost layer by adopting phi 113 mm bit and coring; the drilling process of the feeding drill hole comprises the following steps: adopting phi 215 mm and phi 245mm roller bit to drill coreless into bedrock, then setting phi 168 mm protective wall casing pipe and fixing pipe with cement slurry, drilling the bedrock section to 2.0m below goaf or roadway floor by adopting phi 133 mm bit, and coring;

a first feeding line and a second feeding line are respectively arranged on two sides of the waterproof curtain investigation and control line, an old goaf bottom plate right opposite to a first feeding drill hole on the first feeding line has a first depth, an old goaf bottom plate right opposite to a second feeding drill hole on the second feeding line has a second depth, and the first depth is smaller than the second depth;

during grouting, firstly, pouring coarse aggregate quick-setting concrete into the low dead zone through a second feeding drill hole to form a first curtain barrier; then, pouring coarse aggregate rapid-hardening concrete into the high empty area through the first feeding drill hole to form a second curtain barrier; finally, pouring cement-water glass double grout under pressure in the exploration drilling hole between the first curtain barrier and the first curtain barrier;

in the pouring process of the coarse aggregate quick-setting concrete, a polycarboxylic acid high-performance water reducing agent is adopted to reduce the concrete slump, and a quick-setting agent is added into the concrete; adding an organic inert material or an aggregate material into an orifice when concrete is poured; and pouring concrete and the organic inert material/aggregate material into the feeding drill hole in an intermittent staggered pouring mode.

2. The curtain grouting method for large-space large-inclination goaf according to claim 1, characterized in that a plurality of feeding lines are arranged in parallel to the waterproof curtain exploration line, feeding drill holes are constructed on the feeding lines at equal intervals, and the underground goaf is not exposed by the drill holes at both ends of each feeding line.

3. The curtain grouting method for large-space large-inclination goaf according to claim 2, characterized in that the vertical distances between the first feeding line, the second feeding line and the waterproof curtain exploration line are all 2m, and the feeding drilling density on the feeding lines is 4 m.

4. The curtain grouting method for the large-space large-inclination goaf according to claim 1, characterized in that grouting is performed on the exploratory drill hole without the uncovered goaf, and an accelerator with 3% of cement mass is added into the slurry;

the grouting process from thin slurry to thick slurry is adopted, the concentration water cement ratio of primary grouting of the drill hole is 0.9:1-0.8:1, and secondary grouting is 0.8:1-0.7: 1.

5. The curtain grouting method for the large-space large-inclination goaf according to claim 1, characterized in that an intermittent concrete pouring method is adopted, after the concrete of the previous batch is poured and is primarily solidified for 1-4h, the concrete of the next batch is poured, and the operations are repeated to finish the concrete pouring of all batches.

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