CN106381863B - Drilling and grouting composite device for grouting and reinforcing water-rich sand layer and construction process - Google Patents

Abstract

The invention discloses a drilling and grouting composite device for grouting and reinforcing a water-rich sand layer and a construction process, and the drilling and grouting composite device comprises a grouting pipe body, wherein the grouting pipe body is formed by sequentially connecting a plurality of sections of grouting pipes, an expandable grout containing body is sleeved on the outer side of the pipe wall of each grouting pipe, a plurality of grout outlet holes are formed in the pipe wall of each grouting pipe at the positions matched with the grout containing bodies, and grout enters the grout containing bodies from the grout outlet holes of the grouting pipes to expand the grout containing bodies and squeeze the grout containing bodies and the sand layer around the grout containing bodies. The drilling and grouting composite device can realize the integrated operation of drilling and grouting reinforcement in the sand layer. The invention prevents the splitting of the grout to the sand layer and the linear extension of the grout vein in the previous grouting by the containing and self-expansion effects of the grout container on the grout; the slurry is retained around the drill hole, and the effect of compacting a loose sand layer around the drill hole is achieved through expansion of the slurry containing body.

Description

Drilling and grouting composite device for grouting and reinforcing water-rich sand layer and construction process

Technical Field

The invention belongs to the technical field of tunnel, subway and slope management and the like, and particularly relates to a drilling and grouting compound device for grouting and reinforcing a water-rich sand layer and a construction process.

Background

As is known to all, underground engineering or slope management engineering can face serious collapse of surrounding rocks after encountering sand beds. The reason for this is that the sand layer is loose and has no cementation, especially the sand layer rich in water has fluidity under the action of water, once the sand layer is disturbed manually, the sand layer will collapse unstably; when the construction is carried out in a water-rich sand layer, the sand particles are carried by underground water and are sprayed and flow out like flowing water. The safety of engineering and constructors is seriously harmed. At present, the technical problem of grouting reinforcement of sand beds, particularly water-rich sand beds, at home and abroad is mainly shown in the following aspects: firstly, when grouting and drilling are carried out in a sand bed, the hole is difficult to form because the hole wall is seriously collapsed; secondly, when grouting and reinforcing are carried out in the sand layer, due to the non-caking property among the sand grains, the grout can be freely split and moved outwards under extremely small pressure to form extremely narrow linear grout veins which extend towards the far end infinitely, the grout is difficult to be retained around the drill hole and is difficult to play a role in reinforcing the sand layer around the drill hole, an effective grout vein self-supporting system with higher strength cannot be formed, and the grouting and reinforcing effect on the whole sand layer within the controllable range of the drill hole is poor. Therefore, in the excavation process after the grouting is finished, the phenomenon of extensive collapse can still occur except that the existence of grout veins is still difficult to find. What is needed to be solved at present is how to control the grout injected into the sand layer to be effectively controlled around the drill hole, so that not only the loose sand around the drill hole is compacted (but not split), but also the injected grout is retained around the drill hole, so that a grout vein support body with certain support strength is formed in a grouting reinforcement area, and the permeability of the sand layer is improved through the compaction effect on the sand layer, and the flow of underground water entering the engineering through the sand layer is reduced, so that the safe construction of the treatment engineering in the sand layer and the safe and normal operation in the later period of the engineering are ensured.

Disclosure of Invention

The invention aims to overcome the defects of the prior art, and provides a drilling and grouting compound device for grouting and reinforcing a water-rich sand layer, which aims to effectively solve the technical problems that slurry is difficult to remain around a drill hole and the sand layer is compacted during grouting of the sand layer, and can realize the integrated operation of drilling and grouting reinforcement in the sand layer.

The invention also provides a grouting device for grouting and reinforcing the water-rich sand layer, which can realize the effect of extruding and compacting the water-rich sand layer and improve the permeability of the sand layer.

The invention also provides a construction process of the drilling and grouting composite device for grouting and reinforcing the water-rich sand layer, a surrounding rock self-supporting system with higher strength can be formed through multiple drilling holes for grouting, and the stability of the whole structure of the sand layer in a drilling control range is realized by combining the compacted sand layer.

In order to achieve the purpose, the invention adopts the following technical scheme:

the grouting device for grouting and reinforcing the water-rich sand layer comprises a grouting pipe body, wherein the grouting pipe body is formed by sequentially connecting a plurality of sections of grouting pipes, an expandable slurry containing body is sleeved on the outer side of the pipe wall of each grouting pipe, a plurality of slurry outlet holes are formed in the pipe wall of each grouting pipe at the positions matched with the slurry containing bodies, and slurry enters the slurry containing bodies from the slurry outlet holes of the grouting pipes to expand and squeeze the slurry containing bodies and the sand layers around the slurry containing bodies. The thick liquid gets into the thick liquid splendid attire body from the slip casting pipe by the grout outlet, sets up the grout outlet and can guarantee the normal outflow of thick liquid, can guarantee the thick liquid and fill the homogeneity of thick liquid splendid attire body. The grout containing bodies outside the grouting pipes connected in sequence can ensure that the grout containing bodies and the sand layers around the grout containing bodies are extruded and compacted.

Preferably, the slurry container is externally wound with a covering protection body when being installed. Avoid when precession drilling, the thick liquid splendid attire body receives the damage.

Further preferably, the coating protection body is spiral, and the coating protection body is of a waterproof structure. The coating protection body is arranged to be spiral, so that the slurry containing body can be better protected from being damaged by the friction of the hole wall.

Preferably, a check valve is arranged between the grouting pipes of adjacent sections. Set up the check valve, guarantee that the thick liquid is full of present thick liquid splendid attire body after, reentrant next thick liquid splendid attire body can guarantee that each thick liquid splendid attire body homoenergetic is full of.

Preferably, both ends of the outer side of the grout containing body are connected to the pipe wall of the grouting pipe through binding bands. The two ends of the grout containing body are ensured to be closed, and the grout is ensured to prop up the grout containing body and then squeeze the surrounding sand layer tightly.

Further preferably, a sealing element is arranged between the two ends of the outer side of the grout container and the pipe wall of the grouting pipe. The two ends of the slurry containing body are completely sealed, and slurry leakage cannot occur.

The drilling and grouting compound device for grouting and reinforcing the water-rich sand layer comprises the grouting device, wherein one end of the grouting pipe body is connected with a drill bit; when drilling, the other end of the grouting pipe body is connected with a drill rod; during grouting, the other end of the grouting pipe body is connected with a grouting joint. The drilling and grouting dual-purpose of the grouting pipe can be realized, the grouting pipe can be used as a drill rod when drilling, grouting is completed when grouting, when the grouting pipe drills into a water-rich sand layer, slurry enters a slurry containing body through the grouting pipe, the slurry containing body expands to extrude the surrounding sand layer compactly, and the slurry has a high-strength surrounding rock self-supporting effect after solidification.

Preferably, the drill bit is a conical four-wing drill bit, and the rotary diameter of the drill bit is larger than the outer diameter of the slurry containing body. The diameter of the hole drilled by the drill bit can ensure that a grouting pipe, a slurry containing body and the like can smoothly enter, and further the friction between the slurry containing body and a sand layer is avoided.

Furthermore, a valve is arranged between the grouting joint and the grouting pipe body. The start and stop of the slurry injection is controlled by a valve.

Furthermore, a pressure gauge is connected to the grouting joint. The pressure condition in the grouting pipe can be accurately detected, grouting can be stopped as soon as possible when the pressure limit is reached, and the grouting pipe, a grout containing body and the like are prevented from being burst due to overlarge pressure.

Preferably, a flushing three-way valve is further arranged at the grouting joint. And after grouting is finished, the structures such as the grouting joint can be flushed by clear water.

And a plug is arranged between the grouting pipe body and the drill bit. Avoid the thick liquid to flow by the drill bit, influence the slip casting and consolidate the effect.

The construction process of the drilling and grouting composite device for grouting and reinforcing the water-rich sand layer comprises the following steps:

(1) drilling the drilling and grouting composite device into a set position in the water-rich sand layer, and connecting the end part of the grouting pipe body with a grouting joint;

(2) starting a grouting system, and filling a plurality of grout containers with grout in sequence; in the filling process, when the current grout containing body expands to the limit position, the check valve between the current grouting pipe and the next grouting pipe is opened, and the next grout containing body is filled with grout;

(3) before the grout enters the next grout containing body, the grout in the current grout containing body begins to solidify, and the grout containing body compacts the surrounding water-rich sand layer to form a compacted layer;

(4) and (4) repeating the steps (1) to (3), arranging the drilling and injecting composite devices in the water-rich sand layer in a quincunx shape, and matching the mutually compacted layers to form an integral compaction effect.

Preferably, the slurry is cement-water glass slurry, and the volume ratio of cement to water glass of the cement-water glass slurry is 1:1-3: 1.

The working principle of the invention is as follows:

the end part of the grouting pipe body is connected with a drill bit, and when drilling, the other end part of the grouting pipe body is connected with a drill rod to realize drilling; when grouting is carried out after drilling, the other end of the grouting pipe body is connected with a grouting system, grout enters the grout containing body from the grouting pipe body, and the grout containing body further expands to extrude the grout containing body and sand layers around the grout containing body, so that loose sand layers are compacted, and the self-supporting effect of surrounding rocks is achieved.

The invention has the beneficial effects that:

the invention can realize the effect of extruding and compacting the water-rich sand layer, improve the permeability of the sand layer and reduce the flow of underground water entering the engineering through the sand layer so as to ensure the safe construction of the engineering in the sand layer and the safe and normal operation of the engineering in the later period.

The drilling and grouting composite device can realize the integrated operation of drilling and grouting reinforcement in the sand layer.

The invention solves the technical problems that the grout vein appears after the grout enters the sand layer and extends linearly to the far end without limit, and the grout is difficult to be reserved around the drill hole.

The invention prevents the splitting of the grout to the sand layer and the linear extension of the grout vein in the previous grouting by the containing and self-expansion effects of the grout container on the grout; the slurry is retained around the drill hole, and the effect of compacting a loose sand layer around the drill hole is achieved through expansion of the slurry containing body.

The slurry filled in the expanded slurry containing body has higher strength after being solidified, a surrounding rock self-supporting system with higher strength can be formed through a plurality of drill holes, and the compacted sand layer is combined, so that the stability of the whole structure of the sand layer in the control range of the drill holes is realized, the permeability of the sand layer in the range of the grouting reinforcement body to the surrounding underground water is reduced, and conditions are created for the safety construction of excavation engineering or reinforcement engineering and the safety in engineering operation.

Drawings

FIG. 1 is a schematic view of drilling and installing a drilling and grouting composite device in a sand bed;

FIG. 2 is a schematic diagram illustrating the principle of a sand layer around a pulp bag I filled with pulp and compacted after expansion;

FIG. 3 is a schematic diagram showing the principle of the compacted surrounding sand layer after the pulp bag II is filled with the pulp and expanded;

FIG. 4 is a schematic view showing the principle of the compacted sand layer around the slurry bag III after the slurry bag III is filled with slurry and expanded;

FIG. 5 is a diagram showing the grouting reinforcement and the compaction effect of the surrounding sand layer after the single-hole grouting is finished;

FIG. 6 is a cross-sectional view of the sand bed in the control range of all the holes being grouted to reinforce and compact the sand bed;

FIG. 7 is a partially enlarged view showing the principle that a check valve is opened by high-pressure slurry and slurry is filled into the next slurry bag;

in the figure, 1 grouting pipe, 2 drilling holes, 3 grouting bags I, 4 waterproof adhesive tapes, 5 iron binding tapes, 6 grouting bags II, 7 water-rich sand layers, 8 grouting bags III, 9 conical four-wing drill bits, 10 rock walls, 11 quick setting grout, 12 grouting bags I, 13 expanded grouting bags I, 14 compacted sand layers I, 15 check valves I, 16 grout outlet holes, 17 check valves II, 18 plugs, 19 opened check valves I, 20 grouting bags II, 21 expanded grouting bags II, 22 compacted sand layers II, 23 opened check valves II, 24 grouting bags III, 25 expanded grouting bags III, 26 compacted sand layers III, 27 compacted sand layers as a whole, 28 grouting bags, 29 grouting joints, 30 three-way pressure gauges, 31 valves and 32 flushing.

Detailed Description

The invention is further illustrated with reference to the following figures and examples.

The structure of the drilling and grouting compound device mainly comprises: a plurality of sections of grouting pipes 1; the grout containing bodies (namely the grout bag I3, the grout bag II 6 and the grout bag III 8) are sleeved on each section of the grout pipe 1, the two ends of the grout pipe 1 are tightly bound, and the grout bag can expand after being filled with grout; the grouting bag is made of cloth into a barrel shape, two ends of the grouting bag are bound on the grouting pipe, and the grouting bag is overlapped on the grouting pipe during drilling. After the grout is injected, it slowly opens and expands during the grouting.

A grout outlet 16 cut on each section of grouting pipe 1 to fill the grout in the grout containing body; in order to prevent the loss of the grout entering the grout containing body, iron binding tapes 5 and sealant are used for binding the two ends of the grout containing body on the grouting pipe 1; the check valve is positioned between the adjacent grouting pipes 1 containing the grout containers and can be used for sequentially grouting different grout containers, and the check valve also plays a role in preventing the backflow of the grout; the front end of the grouting pipe 1 is connected with a hard alloy conical four-wing drill bit 9; a valve 31, a pressure gauge 30, a grouting joint 29 and the like which are sequentially arranged at the rear end of the grouting pipe 1 during grouting; in order to meet the drilling requirement, the grout container is attached to the surface of the grouting pipe 1 in an overlapped manner, and is wound by a coating protective body (a waterproof adhesive tape 4 is adopted in the embodiment) to prevent the grout container from being loosened and damaged. In order to prevent the slurry bag which is not filled with slurry in the drilling process from being damaged by the friction of the hole wall, the slurry bag is tightly wound on the wall of the grouting pipe and is bound by a waterproof adhesive tape. The waterproof adhesive tape has the advantages that the waterproof adhesive tape is flexible and can be disconnected when the pulp bag expands, and the expansion of the pulp bag cannot be influenced. The waterproof tape may be replaced with other materials. As long as it can perform the binding and breaking functions. A plug 18 is arranged between the grouting pipe 1 and the conical four-wing drill bit 9.

The manufacturing steps of the drilling and grouting composite device are as follows:

1. according to the requirement of the design scheme on the grouting reinforcement depth, the length of the drilling and grouting compound device and the specification and the material of the grouting pipe are selected, the drilling and grouting compound device consists of a plurality of sections, and the length of each section of grouting pipe 1 (one grouting pipe can be arranged under possible circumstances); determining the length of the pulp bag and the diameter of the pulp bag after expansion corresponding to each section of the grouting pipe 1; the diameter and the number of the grout outlet holes 16 cut on each section of the grouting pipe 1; the pulp bag is made of soft and compact non-woven fabric and is sewn into a cylinder shape.

2. The grout bag I3, the grout bag II 6, the grout bag III 8 and the like are sleeved on the corresponding grouting pipes 1, two ends of the grout bag are firmly bound on the grouting pipes 1 by using iron binding belts 5, and sealant can be added at the contact positions of the grout bag and the grouting pipes 1 before binding. During the grouting process, the air in the grouting pipe and the pulp bag is discharged from the cloth gap of the pulp bag by the pulp. When liquid is required to be filled in the grout bag after the binding, the phenomenon that grout injected into the grout bag leaks at the binding position cannot occur under certain pressure. After binding, the binding quality of the pulp bags can be checked by water or slurry. Then the grout bag is wound on the grouting pipe 1 and is tightly bound by the waterproof adhesive tape 4, so that the grout bag is tightly attached to the grouting pipe 1, and the waterproof adhesive tape 4 can be automatically pulled apart in the process of expanding the grout bag after grouting. The slurry bag is required not to be loosened and damaged when drilling in the drill hole.

3. After each section of grouting bag is bound with the grouting pipe 1 to be qualified, the grouting pipe 1 is connected, a check valve is arranged between every two adjacent grouting pipes 1 with the grouting bags, and the connectedness between the adjacent grouting pipes 1 is isolated by the check valve. The check valve cannot be installed reversely.

4. At the front section of the grouting pipe 1, the diameter of a hard alloy conical four-wing drill bit 9 is selected according to the diameter of a grout bag wound on the grouting pipe 1 and is connected with the grouting pipe 1 at the most front end. A plug 18 is arranged between the grouting pipe 1 and the conical four-wing drill bit 9.

5. In addition, only after drilling is finished, grouting parts such as a valve 31, a flushing tee 32, a pressure gauge 30, a grouting joint 29 and the like can be installed in sequence during grouting.

And finishing the manufacturing of the drilling and grouting composite device.

And (3) installing the drilling and grouting composite device in the drill hole:

1. the grouting pipe 1 of the drilling and grouting compound device is connected to a drill rod, and the drill rod is clamped by a gyrator after passing through a gyrator of a drilling machine. The hard alloy conical four-wing drill bit 9 arranged at the top end of the drilling and grouting compound device is aligned to the hole opening design position of a drilled hole through a drill, after the shaft center of the grouting pipe is corrected to be coincident with the designed angle of the drilled hole, the drill is started, the drill drives the drill rod, the grouting pipe 1 and the conical four-wing drill bit 9 to rotate together, and torque and pressure required by the drilling of the conical four-wing drill bit 9 are transmitted to the conical four-wing drill bit 9 through the drill rod and the grouting pipe 1.

2. As the conical four-wing drill bit 9 drills in the sand layer, the grouting pipe 1 attached with the slurry bags gradually enters the drilled hole. And after the drill hole reaches the designed depth, all the grouting pipes with the grouting bags enter the drill hole, stopping drilling, and disconnecting the grouting pipes 1 from the drill rod. In the drilling construction process, flushing liquid is not used. Because the surrounding rock is a loose sand layer, the drilling and grouting compound device can be smoothly installed in the drill hole without using flushing liquid.

The grouting operation process of the drilling and grouting composite device and the technical requirements thereof are as follows:

1. after the drilling and grouting compound device is installed in a drill hole and the drill rod is removed, a valve 31, a flushing tee 32, a pressure gauge 30 and a grouting connector 29 are sequentially connected at the outer end of the grouting pipe 1 exposed out of the drill hole and are connected with an external grouting system through the grouting connector 29.

2. Starting an external grouting system, injecting grout into the grout bag I3 through the grouting connector 29, the grouting pipe 1 and the grout outlet 16 by the grouting system, gradually expanding the grout bag I3 along with the increase of the injected grout, increasing the pressure of the grout on the grout bag I3 along with the increase of the grout amount in the grout bag, and pushing loose sand particles around the expanded grout bag I3 outwards by the expanded grout bag I3 so as to compact the loose sand layer around, wherein the sand layer is compacted by the grout bag I3 to form a compacted sand layer I14. When slurry is injected into the slurry bag I3, the check valve I15 is required to be always kept in a closed state.

3. After thick liquid bag I3 expands to extreme position, the thick liquid in slip casting pipe 1 can step up fast, and the check valve I15 can be opened to the thick liquid of higher pressure after stepping up, and the thick liquid can enter into second section slip casting pipe 1 to in entering into thick liquid bag II 6 through the play thick liquid hole 16 on second section slip casting pipe 1, the process of the expansion of repeated thick liquid bag I3 and extrusion sand layer on every side. In fact, when the grout enters the next grout bag, the grout in the current grout bag begins to solidify and cannot flow back into the grouting pipe through the grout outlet hole, so that the expanded grout bag cannot shrink.

4. Similarly, after the pulp bag II 6 expands to the limit and the pressure rises, the pulp can open the check valve II 17, the pulp enters the pulp bag III 8 through the pulp outlet holes 16 on the grouting pipe 1 and the third section of grouting pipe 1, and the effect of squeezing the sand layer around the pulp bag III 8 is achieved after the pulp bag III 8 expands.

5. Through installing the drilling and grouting composite device in a plurality of intensive drilling holes and grouting, the effect of compacting and reinforcing the whole sand layer in the control range of all designed drilling holes is achieved. The aim of safe and smooth excavation of engineering or surrounding rock reinforcement is achieved through self-supporting capacity formed by high strength after the sand layer is integrally compacted and the slurry in the slurry bag is solidified.

The grouting operation process requires the following steps:

1. the grouting pipes 1 are connected by screw threads. As the depth of the drilled hole increases, the grout bag III 8, the grout bag II 6 and the grout bag I3 are connected in this order and installed in the drilled hole in this order.

2. The drill bit revolution diameter must be larger than the diameter of the grout bag wound around the grout tube 1, or the grout bag may be broken during drilling.

3. Before the drilling and grouting compound device is conveyed into a drill hole, the expansion diameter of the slurry bag, the pressure of the slurry bag cannot be damaged, and after the iron binding bands are bound on the grouting pipe at the two ends of the bag barrel, the pressure of the slurry bag without leakage and the like are determined on site through experiments so as to determine the maximum filling pressure value of slurry in the slurry bag and the expansion limit pressure value of the slurry bag.

4. The opening pressure of the steel ball of the check valve is slightly higher than the expansion limit pressure of the pulp bag. The slurry bag is prevented from being fully expanded when the slurry bag is not filled with slurry, the check valve is opened, the slurry bag is prevented from leaking into another slurry bag, and the squeezing effect on the surrounding sand layer cannot meet the requirement.

5. The grout injected into the grout bag is quick-setting grout, and can be double-grout or single-grout. However, with any slurry, control of the initial setting time of the slurry must be determined by field testing. The principle is that the grout can be solidified and formed in a short time after entering the front grout bag and fully expanding the grout bag according to the sequence, and the situation that the grout in the grout bag flows back through the grout outlet hole to cause the retraction of the expanded grout bag when the check valve is opened after the pressure of the grout is increased is prevented. The initial setting time of the injected slurry is required to be that the last slurry bag is smoothly filled, the slurry entering all the slurry bags does not have a backflow phenomenon after the slurry is completely expanded, and the slurry reaches a setting state in a short time.

Example (b): a certain section of advanced curtain grouting on the Qingdao subway No. 2 line meets a water-rich quicksand layer, the water spraying phenomenon in a drill hole appears in the drilling construction in the water-rich quicksand layer, and a large amount of sand grains are contained in water to gush out. The conventional slurry injected through the drill hole is difficult to be retained around the drill hole, and the phenomenon of sand blasting and water gushing repeatedly occurs at the same position when the drill hole is re-drilled in the same drill hole. The field practice proves that the traditional grouting reinforcement scheme is difficult to work in the water-rich sand layer. In addition, in the excavation of a test grouting section selected on site, the grout injected into a drilling hole linearly extends to the periphery, so that a grouting reinforcement body with a large area is difficult to form. The slurry is lost distally in a cleavage manner. And does not provide an effective packing effect on the loose sand layer. Therefore, the grouting effect is poor, the sand layer after grouting has almost no self-stabilization capability, and collapse occurs after slight disturbance, and water gushing is accompanied.

Through repeated tests and repeated research and exploration on the grouting principle in the sand bed on site, the drilling and grouting composite device is implemented, the effective reinforcement of the sand bed is realized, and the satisfactory grouting effect is achieved.

The invention is further described with reference to the accompanying drawings and specific embodiments:

1. according to the design scheme of grouting reinforcement in the water-rich sand layer 7 adjusted by the test, the design depth of the drill hole 2 is 9m, the expansion limit diameters of a slurry bag I3, a slurry bag II 6 and a slurry bag III 8 in the grouting test in the water-rich sand layer 7 are about 180mm, and the thickness of the water-rich sand layer 7 which can be compacted is 0.2 m; therefore, according to the grouting capacity requirement, three sections of grouting pipes 1 are selected and adopted, and the length of each section of grouting pipe 1 is 3 m; therefore, the expansion length of each section of the pulp bag is 2.5m, and two ends of each section of the pulp bag are reserved with 250mm respectively to be used as parts for binding the pulp bags by using the iron binding belts 5; the grouting pipe 1 is a seamless steel pipe with the diameter of 42mm, the pipe wall of each section of grouting pipe 1 is wrapped by a part of the grouting pipe in the slurry bag, and slurry outlet holes 16 with the diameter of 8mm are processed, and the slurry outlet holes 16 are uniformly distributed at the interval of 0.2 m; the diameter of the pulp bag is 180mm after expansion; according to the field grouting test, the slurry bags are required to bear the pressure of 3.0Pa without leakage and breakage after being bundled; the check valve I15 and the check valve II 17 are required to be opened under the slurry pressure of 3.2-3.5 MPa; the slurry pressure can be controlled by observing the pressure gauge 30 reading. The diameters of the check valve I15 and the check valve II 17 are consistent with those of the grouting pipe 1, and the check valves and the grouting pipe 1 are connected through screw threads; when the grout bags are attached to the corresponding grouting pipes 1 and tied up by the waterproof adhesive tapes 4, the grout bag cylinders are overlapped and tightly covered on the walls of the grouting pipes in the left-hand direction and are tied up by the waterproof adhesive tapes 4, the tying direction of the waterproof adhesive tapes 4 is consistent with the overlapping direction of the grout bags, and the grout bags after being tied up are prevented from being damaged by friction of the hole walls when rotating in the right direction along with the grouting pipes in the drill holes 2.

2. Through measurement, the diameters of the bundled slurry bags I3, II 6 and III 8 are between 125 and 137mm, so that the hard alloy conical four-wing drill bit 9 with the diameter of 150mm is selected, the hard alloy conical four-wing drill bit 9 is directly connected with the grouting pipe 1, and a plug 18 is arranged between the grouting pipe 1 and the hard alloy conical four-wing drill bit 9 before connection.

3. Connecting a grouting pipe 1 of the drilling and grouting composite device with a drill rod positioned in a chuck of a drilling machine gyrator, aligning the center of a hard alloy conical four-wing drill bit 9 at the front end of the drilling and grouting composite device with the center point of a drilling hole site designed on a rock wall 10 through the drilling machine after the drill rod is clamped by the chuck of the drilling machine, starting the drilling machine to rotate after the angle between the drill rod and the grouting pipe 1 is adjusted to accord with the designed angle of the drilling hole, and transmitting torque and pressure required by the hard alloy conical four-wing drill bit 9 through the drilling machine and the grouting pipe 1. The hard alloy conical four-wing drill bit 9 rotates and drills in the water-rich sand layer 7 under the action of the pressure transmitted by the grouting pipe 1, after the drilling depth is 9.5m, the drilling and grouting compound device is completely installed in the drill hole 2.

4. The joint of the drill rod and the grouting pipe 1 is disassembled, one end of the grouting pipe at the joint is sequentially connected with a valve 30, a flushing tee joint 32, a pressure gauge 30 and a grouting joint 29, the grouting joint 29 is connected with a high-pressure rubber pipe connected with an external grouting system, and the external grouting system comprises a grouting pump and a high-pressure rubber pipe. After the connection is finished, the grouting pump is started, and the prepared quick setting grout 11 is sequentially injected into grout bags at different positions through the grouting joint 29 and the grouting pipe 1.

5. Firstly, quick setting grout 11 enters a grout bag I3 through a grouting joint 29, a first section of grouting pipe 1 and a grout outlet 16 on the pipe wall of the first section of grouting pipe, the grout bag I3 is expanded slowly along with the increase of the injected grout, the grout bag I3 is expanded continuously by the grout 12 filled in the grout bag I under the action of pressure after the grout is injected continuously, a waterproof adhesive tape 4 outside the grout bag I3 is broken, and loose sand grains around the expanded grout bag I13 are pushed outwards, so that a surrounding sand layer is compacted, and a compacted sand layer I14 is formed. When the quick-setting slurry 11 is injected into the slurry bag I3 and reaches the initial setting time in terms of time, the injected quick-setting slurry is gradually solidified, and the solidified slurry is difficult to flow back, so that the expanded slurry bag I3 cannot shrink, and the continuous extrusion on a sand layer is maintained;

6. after the grout bag I3 expands to the limit position, namely fully expands, the quick setting grout 11 is difficult to continue to enter, the pressure intensity of the grout in the first section of grouting pipe 1 can be rapidly increased, the boosted grout can open the check valve I15, the grout enters the second section of grouting pipe 1 through the opened check valve I19 and enters the grout bag II 6 through the grout outlet 16 in the second section of grouting pipe 1, the grout 20 filled in the grout bag II can expand the grout bag II 6, the waterproof adhesive tape 4 outside the grout bag II 6 is broken, the expanded grout bag II 21 extrudes the surrounding sand layer, and the compacted sand layer II 22 is formed. Similarly, after the slurry bag II 6 expands to the limit position, slurry is difficult to continue to enter, at the moment, the slurry in the second section of the grouting pipe 1 can be quickly pressurized, the slurry with higher pressure after pressurization can open the check valve II 17, the slurry enters the third section of the grouting pipe 1 through the opened check valve II 23 and enters the slurry bag III 8 through the partial slurry outlet hole 16, the slurry 24 filled in the slurry bag III 25 can expand the slurry bag III 8, the waterproof adhesive tape 4 outside the slurry bag III 25 is broken, and the expanded slurry bag III 25 extrudes the surrounding sand layer to form an extruded and compacted sand layer III 26.

At the moment, after the pressure intensity rises to the limit value of expansion of the slurry bag III 8, stopping grouting, closing the grouting pump, and closing the valve 30 at the outer end of the grouting pipe 1. And opening the flushing tee joint 32 connected with the valve 30 as soon as possible, and starting the grouting pump to flush residual grout in the external grouting system and the pipeline at the outer end of the flushing tee joint 32. After flushing, the valve is removed between the flush tee 32 and the valve 30.

The single-hole grouting reinforcement process performed by the drilling and grouting composite device is completely completed.

7. According to the expansion limit diameter of the slurry bag and the compressed thickness of the sand layer obtained by the experiment, the distance between grouting drill holes is designed to be 0.4m, and the drill holes are arranged in a quincunx shape. After the drilling is completely constructed and the grouting is finished, the grout 28 filled in the grout bag is solidified, so that the overall grouting reinforcement and compaction effects on the sand layer in the drilling control area are achieved, and the compacted sand layer 27 is formed integrally.

8. According to repeated field experiments, cement-water glass double-liquid slurry is selected and used for ensuring the grouting safety and the grouting reinforcement effect. The cement label is 42.5R, and the density of the cement paste (A liquid) is controlled to be 1.50-1.55g/cm³In the meantime. The modulus of the water glass (B liquid) is controlled to be about 2.6-2.8. The concentration is between 38 and 40 Be'. The volume ratio of the cement paste (liquid A) to the water glass (liquid B) is 3:1, and the initial setting time of the quick-setting cement paste 11 after mixing under the parameters is 30 seconds.

Although the embodiments of the present invention have been described with reference to the accompanying drawings, it is not intended to limit the scope of the present invention, and it should be understood by those skilled in the art that various modifications and variations can be made without inventive efforts by those skilled in the art based on the technical solution of the present invention.

Claims (4)

1. The grouting device for grouting and reinforcing the water-rich sand layer is characterized by comprising a grouting pipe body, wherein the grouting pipe body is formed by sequentially connecting a plurality of sections of grouting pipes, an expandable grout containing body is sleeved on the outer side of the pipe wall of each grouting pipe, a plurality of grout outlet holes are formed in the pipe wall of each grouting pipe at the positions matched with the grout containing bodies, and grout enters the grout containing bodies from the grout outlet holes of the grouting pipes to expand the grout containing bodies and squeeze the grout containing bodies and the sand layers around the grout containing bodies;

a coating protection body is wound outside the slurry containing body; the wrapping protective body is spiral, and the binding direction of the wrapping protective body is consistent with the stacking direction of the pulp bags; a check valve is arranged between the grouting pipes of adjacent sections, and the opening pressure of a steel ball of the check valve is slightly higher than the expansion limit pressure of the slurry bag; the two ends of the outer side of the grout containing body are connected to the pipe wall of the grouting pipe through binding belts;

and sealing elements are arranged between the two ends of the outer side of the grout container and the pipe wall of the grouting pipe.

2. The drilling and grouting compound device for grouting and reinforcing the water-rich sand layer is characterized by comprising the grouting device of claim 1, wherein one end part of the grouting pipe body is connected with a drill bit; when drilling, the other end of the grouting pipe body is connected with a drill rod; during grouting, the other end of the grouting pipe body is connected with a grouting joint; the drill bit is a conical four-wing drill bit, and the rotating diameter of the drill bit is larger than the outer diameter of the slurry containing body; a plug is arranged between the grouting pipe body and the drill bit;

a valve is arranged between the grouting joint and the grouting pipe body; the grouting joint is connected with a pressure gauge;

and a flushing three-way valve is also arranged at the grouting joint.

3. The process for constructing a composite device according to claim 2, comprising the steps of:

(1) drilling the drilling and grouting composite device into a set position in the water-rich sand layer, and connecting the end part of the grouting pipe body with a grouting joint;

(2) starting a grouting system, and filling a plurality of grout containers with grout in sequence; in the filling process, when the current grout containing body expands to the limit position, the check valve between the current grouting pipe and the next grouting pipe is opened, and the next grout containing body is filled with grout;

(3) before the grout enters the next grout containing body, the grout in the current grout containing body begins to solidify, and the grout containing body compacts the surrounding water-rich sand layer to form a compacted layer;

(4) and (4) repeating the steps (1) to (3), arranging the drilling and injecting composite devices in the water-rich sand layer in a quincunx shape, and matching the mutually compacted layers to form an integral compaction effect.

4. The construction process according to claim 3, wherein the slurry is cement-water glass slurry, and the volume ratio of cement to water glass of the cement-water glass slurry is 1:1-3: 1.