Radial consolidation grouting construction method for water tunnel engineering

Abstract

The invention discloses a radial consolidation grouting construction method for water tunnel engineering, which is characterized by comprising the following steps: step 1, laying grouting hole sites; secondly, auxiliary equipment is installed; step 3, setting up and debugging the pulping station; fourthly, drilling equipment is installed; step 5, drilling; step 6, drilling and flushing; step 7, carrying out a water pressing experiment; step 8, pulping; ninthly, grouting equipment is installed; and 10, grouting. The tunnel is reinforced through radial consolidation grouting, the safety requirement of underground cavern tunneling construction is met, meanwhile, the uniformity, integrity, non-deformability, compressive strength and elastic modulus of tunnel base rock mass are improved through consolidation grouting, and rock mass deformation and differential settlement are reduced.

Description

Technical Field

[0001] The invention relates to the technical field of water conveyance tunnel construction methods, and in particular to a radial consolidation grouting construction method for a water conveyance tunnel project. Background Art

[0002] Consolidation grouting is a construction technology that improves the mechanical properties of rocks in areas with geological defects such as rock foundation joints, developed cracks or broken zones, improves the uniformity, integrity and deformation resistance, compressive strength and elastic modulus of the tunnel foundation rock mass, and reduces rock deformation and uneven settlement. It has been widely used in tunnel construction projects.

[0003] In the tunnel construction project, the tunnel is reinforced by radial consolidation grouting to meet the safety requirements of underground cavern excavation construction. At the same time, the consolidation grouting improves the uniformity, integrity, deformation resistance, compressive strength and elastic modulus of the tunnel foundation rock, reducing rock deformation and uneven settlement. Summary of the invention

[0004] The purpose of the present invention is to provide a radial consolidation grouting construction method for a water conveyance tunnel project, which completes the reinforcement treatment of the tunnel, not only improving the uniformity, integrity, deformation resistance, compressive strength and elastic modulus of the tunnel foundation rock mass, but also reducing rock mass deformation and uneven settlement.

[0005] The present invention is implemented by the following technical solution: A radial consolidation grouting construction method for a water conveyance tunnel project comprises the following steps:

[0006] Step 1: Arrange the grouting holes. The surveyors arrange the holes according to the tunnel construction drawings, arrange the holes in a plum blossom pattern according to the requirements of the measures, and hang signboards at the locations where the holes are arranged.

[0007] Step 2: Installation of auxiliary equipment: erection of construction racks, laying of air, power and water supply pipes, installation of sewage system, sorting of auxiliary equipment according to site conditions, inspection of equipment after installation, and putting into use after inspection and compliance;

[0008] Step 3: Build and debug the pulping station. Under the guidance of the manufacturer, set up a centralized pulping station outside the cave and a temporary pulping station inside the cave according to the grouting demand. The pulping station includes a mixer, a filter screen, a pulp storage barrel and a delivery pump. The mixer is connected to the pulp storage barrel through the filter screen, and the delivery pump is connected to the pulp storage barrel. The pulping station is put into use after debugging.

[0009] Step 4: Drilling equipment installation; the drilling equipment adopts a crawler-type down-the-hole drill, and a water spraying device for water spraying and cleaning is installed in the drilling equipment, and the water spraying device moves synchronously with the drilling equipment;

[0010] Step 5: Drilling: Drill holes at the locations of the arranged grouting holes by using a crawler-type down-the-hole drill;

[0011] Step 6: Borehole flushing: After drilling, open the hole and use a water spray device to spray clean water to flush out rock powder and other impurities in the hole, and measure and record the hole depth after flushing;

[0012] Step 7: Water pressure test: After flushing the grouting holes, a water pressure test is carried out. The number of radial consolidation grouting water pressure test holes shall not be less than 5% of the total number of holes. The pilot holes shall adopt the single-point water pressure method, and the other holes shall adopt the simple water pressure method.

[0013] Step 8, slurry preparation: water, cement and additives are added to the mixer in the slurry preparation station, mixed by stirring, filtered through a filter screen after mixing, and then sent to the slurry storage barrel, and the prepared slurry is transported by a delivery pump;

[0014] Step nine, installation of grouting equipment; the grouting equipment includes a pressure gauge, flow meter, automatic recorder, control valve and grouting device. The control valve is connected to the delivery pump through a DN25 high-pressure slurry pipe. The grouting conditions are recorded and tested through the pressure gauge, flow meter and automatic recorder.

[0015] Step 10: Grouting: Grouting holes are treated by grouting equipment. According to different site conditions, pure pressure grouting method, group hole parallel grouting method and in-hole circulation grouting method are adopted.

[0016] In order to better realize the present invention, further, in the step one, when there is no water outflow and seepage on the support surface, plum blossom-shaped holes are arranged according to the requirements of the measures; when there is water seepage or gushing in part or everywhere on the initial support surface, plum blossom-shaped holes are arranged according to the requirements of the measures, and the holes are appropriately increased around the water outlet point to ensure the water blocking effect.

[0017] In order to better realize the present invention, further, in the step three, the centralized pulping station outside the cave uses P.042.5 ordinary silicate canned cement. After the preparation of the pulping station is completed, it is transported to the grouting equipment by a cement tank truck with a clean tank body to ensure that the required cement slurry can be provided; the centralized pulping station that has not been used for more than 4 hours needs to be directly discarded and cannot be used for water plugging grouting; the temporary pulping station in the cave uses P.042.5 ordinary silicate bagged cement, and the mixer and mixing barrel are installed and debugged to be qualified. After coming out of the pulping station, it enters the secondary mixing barrel, and after secondary mixing, it enters the delivery pump and is delivered to each grouting point through a DN25 high-pressure slurry pipe.

[0018] In order to better implement the present invention, further, in step 5, the drilling hole diameter is The radial consolidation grouting hole depth is 4.5m. When encountering soft rock or surrounding rock broken hole section, it is difficult to form a hole and the hole collapse is serious. Hot-rolled seamless steel pipe is used to support the hole. The diameter of hot-rolled seamless steel pipe is Wall thickness 3.5mm, single length 4.5mm.

[0019] In order to better implement the present invention, further, in step six, the flushing pressure is 80% of the grouting pressure and is not greater than 1 MPa, and the flushing time is not greater than 15 minutes; flushing is not performed when there are holes adjacent to grouting or the grouting end time is less than 24 hours.

[0020] In order to better implement the present invention, further, in step seven, if water gushing occurs during the drilling process, water blocking grouting may be performed directly without performing a water pressure test.

[0021] In order to better realize the present invention, further, in the step eight, the slurry material must be weighed, and the weighing error is less than 5%. The solid phase materials such as cement are weighed by weight. After the slurry is made, the volume of the slurry is tested by a hydrometer to ensure that the slurry performance meets the engineering requirements.

[0022] In order to better realize the present invention, further, in the step 10, the strength of the shotcrete at the radial consolidation grouting should reach the designed compressive strength value, and there should be no lining construction within 20m around before the radial consolidation grouting can be started; for the special tunnel sections of surrounding rock classes III, IV, and V, the depth of the grouting holes is 4.5m, and full-hole one-time grouting is adopted; the grouting pressure is determined according to on-site experiments.

[0023] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0024] 1. The present invention reinforces the tunnel through radial consolidation grouting, which meets the safety requirements of underground cavern excavation construction. At the same time, the consolidation grouting improves the uniformity, integrity, deformation resistance, compressive strength and elastic modulus of the tunnel foundation rock mass, and reduces rock mass deformation and uneven settlement.

[0025] 2. The present invention realizes the refined management of the grouting process through the construction and debugging of the slurry station and the installation of the grouting equipment, ensures the quality and stability of the slurry, and during the grouting process, adopts different grouting methods for different situations, making the grouting operation more standardized and flexible.

[0026] 3. The present invention has strict requirements on the weighing of slurry materials and the detection of slurry performance, which ensures the stability and reliability of grouting quality. It has corresponding treatment measures for special situations such as water gushing and soft rock, which ensures the smooth progress of construction and the stability of project quality. DETAILED DESCRIPTION

[0027] In order to make the purpose, process conditions and advantages of the present invention more clearly understood, the present invention is further described in detail in conjunction with the following embodiments, but the embodiments of the present invention are not limited thereto. Without departing from the above-mentioned technical ideas of the present invention, various substitutions and changes are made according to the common technical knowledge and customary means in the field, which should all be included in the scope of the present invention. The specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0028] Embodiment 1:

[0029] This embodiment provides a radial consolidation grouting construction method for a water conveyance tunnel project, comprising the following steps:

[0030] Step 1. Arrange the grouting holes. The surveying personnel arrange the holes according to the construction drawings of the tunnel. The arranged hole number consists of six parts: grouting location, type, unit number, direction, ring number, serial number and hole number. For example, the upstream drill hole number of the 5# construction branch tunnel of Kuncheng Tunnel is "5G2-S-5-II-2", which means: the 5th ring No. 2 hole of the 5# construction branch tunnel upstream radial consolidation grouting (G) 2 unit, and the hole sequence is II. When arranging the holes, if there is no water outflow and seepage on the support surface, the holes are arranged in a plum blossom pattern according to the requirements of the measures; for the initial support surface or when there is water seepage and gushing everywhere, the holes are arranged in a plum blossom pattern according to the requirements of the measures, and the holes are appropriately encrypted around the water outlet to ensure the water blocking effect. A signboard with the hole number written on it is hung at the arrangement position.

[0031] Step 2: Installation of auxiliary equipment: erection of construction scaffolding, laying of air, electricity and water supply pipes, installation of sewage system, sorting of auxiliary equipment according to site conditions, inspection of equipment after installation, and putting into use after passing the inspection; sewage system: when setting up a pulping station, dig ditches and collection pits around it to precipitate sewage, discharge clean water, and pile up sediments in a centralized manner and transport them to the waste dump in due course; in the grouting construction area, combined with the diversion and sewage ditch set up in the drainage system during the construction period, the drilling slag and sewage in the construction will be discharged into the sewage treatment system and then into the sedimentation tank for sedimentation treatment; finally, all precipitated impurities, waste slurry, wastewater, etc. will be transported and discharged to the designated location.

[0032] Step three, build and debug the slurry making station. Under the guidance of the manufacturer, set up a centralized slurry making station outside the cave and a temporary slurry making station inside the cave according to the amount of grouting demand. The slurry making station includes a mixer, a filter screen, a slurry storage barrel and a delivery pump. The mixer is connected to the slurry storage barrel through the filter screen, and the delivery pump is connected to the slurry storage barrel. The slurry making station is put into use after debugging. When supplying slurry, the centralized slurry making station outside the cave uses P.042.5 ordinary silicate canned cement. After the preparation of the slurry making station is completed, it is transported to the grouting equipment with a cement tank truck with a clean tank body to ensure that the required cement slurry can be provided. Centralized slurry making stations that have not been used for more than 4 hours need to be directly discarded and cannot be used for water plugging grouting. The temporary slurry making station in the cave uses P.042.5 ordinary silicate bagged cement. The mixer and mixing barrel are installed and debugged to be qualified. After coming out of the slurry station, it enters the secondary mixing barrel, and after secondary mixing, it enters the delivery pump and is transported to each grouting point through a DN25 high-pressure slurry pipe.

[0033] Step 4: Install the drilling equipment; the drilling equipment adopts a crawler-type down-the-hole drill, and a water spray device for water spray cleaning is installed in the drilling equipment, and the water spray device moves synchronously with the drilling equipment.

[0034] Step 5: Drilling: Drill holes at the locations of the grouting holes using a crawler-type down-the-hole drill. The hole diameter is The radial consolidation grouting hole depth is 4.5m. When encountering soft rock or surrounding rock broken hole section, it is difficult to form a hole and the hole collapse is serious. Hot-rolled seamless steel pipe is used to support the hole. The diameter of hot-rolled seamless steel pipe is The wall thickness is 3.5mm and the single length is 4.5mm. The drilling is carried out according to the principle of rows and sequences. The I-sequence holes are made first, and then the II-sequence holes are made between the rings. In the same ring, the I-sequence holes are made first, and then the densified holes are made. The specific arrangement is carried out according to the provisions of the construction drawings. In principle, one hole is drilled and one hole is poured. For holes with a small injection volume, a maximum of 3 holes of the same sequence are drilled in the same ring. For places with a large injection volume, poor geological surrounding rock, and water gushing and seepage, one hole should be drilled and one hole poured.

[0035] Step 6: Borehole flushing; After drilling, open the hole mouth and use a water spray device to spray clean water to flush out the rock powder and other impurities in the hole. Measure and record the hole depth after flushing. The thickness of the bottom sediment after flushing should not be greater than 20cm; the flushing water pressure should be 80% of the grouting pressure and not greater than 1MPa, and the flushing time should not be greater than 15min or until the return water is clean; when there is a hole being grouted nearby or the grouting of the adjacent hole has been completed for less than 24h, the fissure flushing shall not be carried out; after flushing the grouting hole, the hole shall be immediately and continuously grouted. If the interruption time interval exceeds 24h for some reason, the hole shall be flushed again before grouting; when the geological surrounding rock is soft rock and drilling flushing is impossible, grouting operation shall be carried out directly to reinforce the surrounding rock in time; when water gushing occurs during the drilling process, drilling flushing may not be carried out, and water blocking grouting may be carried out directly.

[0036] Step 7, water pressure test: after flushing the grouting holes, a water pressure test is carried out. The number of radial consolidation grouting water pressure test holes shall not be less than 5% of the total number of holes. The pilot holes shall be pressurized by single-point method, and other holes shall be pressurized by simple water pressure method. Stability standard of pressure flow rate: under stable pressure, measure the pressure flow rate every 3 to 5 minutes. When the difference between the maximum and minimum values ​​in four consecutive readings is less than 10% of the final value, or the difference between the maximum and minimum values ​​is less than 1L / min, this section of the test can be ended and the final value shall be taken as the calculated value.

[0037] The water pressure test results are expressed as water permeability q. The calculation formula is as follows:

[0038]

[0039] Where: q-test section water permeability, Lu;

[0040] Q-pressure flow, L / min;

[0041] P-total pressure acting in the test section, MPa;

[0042] L-test section length, m.

[0043] The simple water pressure test pressure is 80% of the grouting pressure and not more than 1MPa. The water is pressed for 20 minutes, and the pressure flow is measured every 5 minutes. The final flow value is taken as the calculated flow, and the result is expressed as the permeability q, which is calculated according to the above formula. When water gushing occurs during the drilling process, the water pressure test can be omitted and water plugging grouting can be carried out directly.

[0044] Step eight, slurry preparation; add water, cement and additives into the mixer in the slurry preparation station, mix them by stirring, filter them through the filter screen after mixing, and then send them into the slurry storage barrel, and transport the prepared slurry through the delivery pump; the slurry materials must be weighed, and the weighing error is less than 5%. Solid materials such as cement are weighed by weight; in the stirring of pure cement slurry, when using an ordinary mixer, it is not less than 3 minutes; when using a high-speed mixer, it is not less than 30 seconds; the slurry is sieved before use, and the time from the start of preparation to the end is less than 4 hours.

[0045] Mix fine cement slurry and stabilized slurry, add water reducing agent and use high-speed mixer. The stirring speed of high-speed mixer is greater than 1200r / min (r is one rotation). The stirring time is determined by experiment. The time from preparation to use up of slurry should not be more than 2h for fine cement slurry, 4h for cement slurry and 6h for cement-clay slurry.

[0046] In the centralized slurry station, pure concentrated cement slurry with a water-cement ratio of 0.5:1 is centrally mixed, and the slurry flow rate should be 1.4-2.0m / s. The density of the slurry is measured at each grouting point, and the slurry is diluted according to the different needs of each grouting point. The slurry temperature is maintained at 5-40℃, and it is considered waste if it is lower or higher than this standard.

[0047] After the slurry is produced, a hydrometer is used to test the slurry volume to ensure that the slurry performance meets the engineering requirements.

[0048] Step nine, installation of grouting equipment; the grouting equipment includes a pressure gauge, flow meter, automatic recorder, control valve and grouting device. The control valve is connected to the delivery pump through a DN25 high-pressure slurry pipe. The grouting conditions are recorded and tested through the pressure gauge, flow meter and automatic recorder.

[0049] Step 10: Grouting. Use grouting equipment to grout the grouting holes. Depending on the site conditions, use pure pressure grouting, group hole parallel grouting, and in-hole circulation grouting. When grouting, it should be noted that the strength of the shotcrete at the radial consolidation grouting should reach the designed compressive strength value, and there should be no lining construction within 20m around before radial consolidation grouting can begin.

[0050] For the special tunnel sections of surrounding rock types III, IV and V, the depth of the grouting holes is 4.5m, and the whole hole is grouting at one time. The grouting pressure is determined according to the actual situation on site.

[0051] According to different surrounding rock conditions and water discharge conditions in tunnel sections, pure cement slurry, cement slurry with water glass and reverse injection can be reasonably used, which can be divided into the following situations:

[0052] A. For tunnel sections with dripping and seepage as the main problem and surrounding rock types of IV and V, use pure cement slurry for injection. When the water blocking effect is poor, use cement slurry plus water glass double slurry for injection, with a volume ratio of 1:0.5.

[0053] B. For surrounding rock with poor stability, fast deformation rate, prone to landslide and roof collapse, visible dripping and seepage, and surrounding rock category V and V special tunnel sections, pure cement slurry is used for pouring. When the water blocking effect is poor, cement slurry plus water glass double liquid slurry is used with a volume ratio of 1:0.5, which solidifies quickly to ensure the stability of the surrounding rock and control the deformation rate.

[0054] C. For soft rock, mudstone, and broken rock mass, where there is no water outlet section and it is difficult to form a hole, hot-rolled seamless steel pipes are used, and the specifications and parameters are consistent with those of the advanced small pipes. The wall thickness is 3.5mm, and the single length is 4.5m. The auxiliary hole is reinforced with pure cement slurry. In case of dripping or seepage, radial grouting with advanced small tubes is adopted. When the water blocking effect of pure cement slurry is poor, cement slurry plus water glass double slurry is used for injection, with a volume ratio of 1:0.5.

[0055] D. For tunnel sections with surrounding rock types I, V and water inrush being the main problem, pure cement slurry shall be used for injection. When the water blocking effect is poor, cement slurry plus water glass double slurry shall be used for injection, with a volume ratio of 1:0.5.

[0056] E. In view of the above situation of using double slurry to plug water, a grouting experiment should be carried out for each grouting tunnel section to determine the reasonable cement slurry mix ratio and double slurry mix ratio; a grouting pipe should be installed in each grouting hole to ensure that the double slurry is fully mixed and the grouting quality is guaranteed; grouting of water glass and cement slurry each uses a grouting pump, the hole mouth uses a three-way connection, and a flow meter and a pressure valve are installed.

[0057] Pure pressure grouting method is adopted. In principle, one pump is used for one hole in radial consolidation grouting. Group holes can also be used for parallel grouting, but the number of parallel holes should not be more than 3, and the pressure should be controlled to prevent the concrete surface or rock surface from lifting. According to the actual situation, the in-hole circulation grouting method can also be used for grouting.

[0058] When grouting, proceed according to the principle of sequencing between rings and reinforcing within the rings; between rings, grout the I-sequence holes first and then the II-sequence holes; within the same ring, grouting is carried out in the order of grouting the I-sequence holes first and then the reinforcing holes.

[0059] Embodiment 2:

[0060] The concentration of radial consolidation grouting slurry can be gradually controlled from a water-cement ratio of 3:1, 1:1, and 0.5:1. The specific concentration should be determined through on-site production in combination with surrounding rock conditions.

[0061] When the grouting pressure remains unchanged and the injection rate continues to decrease, or when the injection rate remains unchanged and the pressure continues to increase, the water-cement ratio does not change; when the injection volume of a certain level of slurry has reached more than 300L, or the grouting time has reached 30min, and the grouting pressure and injection rate have not changed or have changed insignificantly, the water-cement ratio should be thickened by one level; when the injection rate is greater than 30L / min, it can be thickened by skipping levels according to the specific situation.

[0062] When the injection rate of the grouting section is no more than 1 / min under the maximum design pressure, continue grouting for 30 minutes and then the grouting can be terminated.

[0063] After the grouting of the grouting holes is completed, the accumulated water and dirt in the boreholes should be removed, and the holes should be sealed by "full hole grouting method", "duct grouting method" or "parallel sealing method". The number of parallel holes should not exceed 3, and the remaining part of the hole mouth should be filled and smoothed with hard mortar.

[0064] Embodiment three:

[0065] During the grouting process, if grouting or leakage is found, it should be handled according to the specific situation by using methods such as caulking, surface sealing, low pressure, thick slurry, flow limiting, quantity limiting, rest, waiting for setting, and re-grouting.

[0066] When grouting occurs during the grouting process, if the holes through which grouting occurs are ready for grouting, grouting can be carried out simultaneously, and one hole should be grouted with one pump. Otherwise, the holes through which grouting occurs should be plugged immediately. After the grouting of the grouting holes is completed, the holes through which grouting occurs can continue to be drilled and grouted.

[0067] If the grout loses water and becomes thicker during the grouting process, the following measures can be used:

[0068] 1. Increase the grouting pressure appropriately.

[0069] 2. Use segmented blocked cyclic perfusion.

[0070] 3. Use new slurry with the same water-cement ratio for pouring.

[0071] 4. Increase the number of grouting holes.

[0072] If the phenomenon of thickening of the slurry is common and the above treatment measures are not effective, it is necessary to study the use of fine cement slurry, cement bentonite slurry or chemical slurry injection.

[0073] Grouting work must be carried out continuously. If it is interrupted for some reason, it must be handled according to the following principles:

[0074] 1. Shorten the interruption time as much as possible and resume grouting as soon as possible;

[0075] 2. If the interruption time exceeds 30 minutes, flushing should be carried out immediately. If flushing is ineffective, the hole should be swept before re-slurrying;

[0076] 3. When resuming grouting, the grouting should be carried out with the same grouting ratio as before the interruption. If the grouting volume is similar to that before the interruption, the water-cement ratio before the interruption can be used. If the grouting volume is not much less than that before the interruption, the grouting should be gradually thickened;

[0077] 4. After the grouting is resumed, if the grouting amount is much reduced compared to before the interruption and the grouting is stopped within a very short time, the section will be deemed unqualified.

[0078] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification or equivalent change made to the above embodiment based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A radial consolidation grouting construction method for a water conveyance tunnel project, characterized in that: The following steps are involved: Step 1: Arrange the grouting holes. The surveyors arrange the holes according to the tunnel construction drawings, arrange the holes in a plum blossom pattern according to the requirements of the measures, and hang signboards at the locations where the holes are arranged. Step 2: Installation of auxiliary equipment: erection of construction racks, laying of air, power and water supply pipes, installation of sewage system, sorting of auxiliary equipment according to site conditions, inspection of equipment after installation, and putting into use after inspection and compliance; Step 3: Build and debug the pulping station. Under the guidance of the manufacturer, set up a centralized pulping station outside the cave and a temporary pulping station inside the cave according to the grouting demand. The pulping station includes a mixer, a filter screen, a pulp storage barrel and a delivery pump. The mixer is connected to the pulp storage barrel through the filter screen, and the delivery pump is connected to the pulp storage barrel. A DN25 high-pressure pulp pipe is installed on the delivery pump. The pulping station is put into use after debugging. Step 4: Drilling equipment installation: The drilling equipment adopts a crawler-type down-the-hole drill, and a water spraying device for water spraying and cleaning is installed in the drilling equipment. The water spraying device moves synchronously with the drilling equipment; Step 5: Drilling: Drill holes at the locations of the arranged grouting holes by using a crawler-type down-the-hole drill; Step 6: Borehole flushing: After drilling, open the hole and use a water spray device to spray clean water to flush out rock powder and other impurities in the hole, and measure and record the hole depth after flushing; Step 7: Water pressure test: After flushing the grouting holes, a water pressure test is carried out. The number of radial consolidation grouting water pressure test holes shall not be less than 5% of the total number of holes. The pilot hole adopts the single-point water pressure method, and the other holes adopt the simple water pressure method. Step 8, slurry preparation: water, cement and additives are added to the mixer in the slurry preparation station, mixed by stirring, filtered through a filter screen after mixing, and then sent to the slurry storage barrel, and the prepared slurry is transported by a delivery pump; Step 9: Install the grouting equipment. The grouting equipment includes a pressure gauge, a flow meter, an automatic recorder, a control valve and a grouting device. The control valve is connected to the delivery pump through a DN25 high-pressure grouting pipe. The grouting conditions are recorded and tested through the pressure gauge, flow meter and automatic recorder. Step 10: Grouting: Grouting holes are treated by grouting equipment. According to different site conditions, pure pressure grouting method, group hole parallel grouting method and in-hole circulation grouting method are adopted.

2. A radial consolidation grouting construction method for a water conveyance tunnel project according to claim 1, characterized in that: In the step one, when there is no water outflow or seepage on the support surface, plum blossom-shaped holes are arranged according to the requirements of the measures; when there is water seepage or gushing on the initial support surface partly or everywhere, plum blossom-shaped holes are arranged according to the requirements of the measures, and the holes are appropriately increased around the water outlet to ensure the water blocking effect.

3. A radial consolidation grouting construction method for a water conveyance tunnel project according to claim 1, characterized in that: In the step three, the centralized slurrying station outside the cave uses P, 042, 5 ordinary silicate canned cement. After the preparation of the slurrying station is completed, it is transported to the grouting equipment with a cement tank truck with a clean tank body to ensure that the required cement slurry can be provided; the centralized slurrying station that has not been used for more than 4 hours needs to be directly discarded and cannot be used for water plugging grouting; the temporary slurrying station in the cave uses P, 042, 5 ordinary silicate bagged cement, and the mixer and mixing barrel are installed and debugged to be qualified. After coming out of the slurrying station, it enters the secondary mixing barrel, and after secondary mixing, it enters the delivery pump and is transported to each grouting point through a DN25 high-pressure slurry pipe.

4. A radial consolidation grouting construction method for a water conveyance tunnel project according to claim 1, characterized in that: In the step five, the borehole diameter is 89 mm, and the radial consolidation grouting hole depth is 4.5 m. When encountering soft rock or broken surrounding rock sections, it is difficult to form a hole and the hole collapse is serious. Hot-rolled seamless steel pipes are used to support and fix the hole. The hot-rolled seamless steel pipes have a diameter of 42 mm, a wall thickness of 3.5 mm, and a single length of 4.5 mm.

5. A radial consolidation grouting construction method for a water conveyance tunnel project according to claim 1, characterized in that: In step six, the flushing pressure is 80% of the grouting pressure and is not greater than 1 MPa, and the flushing time is not greater than 15 minutes; flushing is not performed when there is a grouting hole nearby or the grouting is completed within 24 hours.

6. A radial consolidation grouting construction method for a water conveyance tunnel project according to claim 1, characterized in that: In step seven, if water gushing occurs during the drilling process, water-blocking grouting may be performed directly without conducting a water pressure test.

7. A radial consolidation grouting construction method for a water conveyance tunnel project according to claim 1, characterized in that: In the step eight, the slurry materials must be weighed with a weighing error of less than 5%. Solid materials such as cement are weighed by weight. After the slurry is made, the volume of the slurry is tested with a hydrometer to ensure that the slurry performance meets the engineering requirements.

8. A radial consolidation grouting construction method for a water conveyance tunnel project according to claim 1, characterized in that: In the step 10, the strength of the shotcrete at the radial consolidation grouting location should reach the designed compressive strength value, and radial consolidation grouting can only be started when there is no lining construction within 20m around; for special tunnel sections of surrounding rock classes III, IV, and V, the depth of the grouting holes is 4 or 5m, and full-hole one-time grouting is adopted; the grouting pressure is determined based on on-site experiments.

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