Construction method of high pressure jet grouting pile in water-rich flowing sand layer

Abstract

The present invention relates to the field of building construction technology, and specifically to a construction method of high-pressure jet grouting piles in water-rich quicksand layers. The drilling and jetting integrated construction method is used to drill holes and jet grout with slurry. In the water-rich quicksand layer, the construction principle of top-down jet grouting is combined with a low-pressure grouting method, which well controls the phenomenon of hole collapse, drill jamming and drill burial. The method has the characteristics of short construction period, high safety performance, maximum economic benefit, saving wall protection materials and high pile quality. It is suitable for various types of highly active permeable layers and is used in urban construction with high environmental protection requirements.

Description

Technical Field

[0001] The invention relates to the technical field of building construction, in particular to a construction method of high-pressure jet grouting piles in a water-rich flowing sand layer. Background Art

[0002] High-pressure jet grouting is to use cement slurry to form a high-pressure jet to cut the soil to achieve the purpose of strengthening the weak soil. Traditional rotary jet grouting methods include single-tube method, double-tube method and triple-tube method. The construction process and parameters are determined according to the test data before construction. When encountering a layer rich in highly active and permeable flowing sand, after on-site pile testing, the phenomenon of drill jamming and drill burial occurred under this geological condition, and it was impossible to drill into the pile. The water-rich flowing sand layer has a large permeability coefficient, strong activity, and poor self-stability. During the construction process, a large amount of water and sand may gushed out, which is extremely harmful to the project. When bentonite or bentonite plus cement slurry is used as a wall protection material, the expected effect can be achieved for soil layers with low water content, but it cannot be achieved for highly permeable flowing sand layers. The phenomenon of drill jamming and drill burial still exists, which causes great damage to construction machinery and tools and causes economic waste, seriously affecting the construction period and pile quality. Summary of the invention

[0003] The present invention aims to solve the above problems, thereby providing a construction method of high-pressure jet grouting piles in water-rich flowing sand layer geology which can ensure the quality of engineering construction.

[0004] The present invention solves the above-mentioned problem by adopting the following technical solution:

[0005] A construction method of high-pressure jet grouting piles in a water-rich sand layer includes the following steps:

[0006] Step 1: Preset and assemble a triple-tube high-pressure jet grouting machine, a jet grouting machine drill rod and a shotcrete drill bit. The axis of the slurry nozzle of the shotcrete drill bit is tilted downward in the horizontal direction. Preset an automatic slurry mixer and equip it with a high-pressure grouting pump to form a slurry mixing system. Preset an air compressor and equip it with an air storage tank to form a compressed air system. Preset a clean water tank and equip it with a high-pressure clean water pump to form a water storage system. Preset a generator set and equip it with a distribution box to form a power generation system.

[0007] Step 2: After the triple-tube high-pressure jet grouting machine, the jet grouting machine drill rod and the shotcrete drill bit are assembled, the verticality of the jet grouting machine drill rod is debugged;

[0008] Step 3: Install the slurry mixing system, compressed air system, water storage system and power generation system on the triple-tube high-pressure jet spraying machine, and check whether the whole system is working normally;

[0009] Step 4: Before construction, test spray on the ground to check whether there is air leakage in the air pipe, water leakage in the water pipe, and check the pressure of the grouting pump;

[0010] Step 5: The drilling and spraying method is the first choice for construction. The spraying drill first sprays cement slurry and then drills down to make holes. After drilling, gas and water are sprayed;

[0011] Step 6: When drilling into the water-rich flowing sand layer, the slurry nozzle of the grouting drill bit is tilted downward, and the grouting is sprayed from top to bottom. The cement + water glass double slurry is used to make slurry, and the gas is used to cut the flowing sand soil, and the double slurry is used to fill;

[0012] Step 7: After penetrating the water-rich sand layer, continue the construction by using the integrated drilling and spraying method in step 5 until the designed pile bottom is drilled, and the slurry, water and air are delivered in time. After reaching the designed spraying pressure, spray grouting is carried out, rotating, lifting and spraying at the same time, spraying grouting from bottom to top, and the rotation and lifting are continuous and uninterrupted;

[0013] Step 8: When the grouting is completed in the double-liquid slurry water-rich flowing sand layer, the low-pressure grouting method is used. The rotary jet drill rod is slowly lifted at this formation position. The grouting drill bit only sprays cement slurry without spraying gas and water.

[0014] Step 9: When the shotcrete drill bit is lifted close to the designed pile top, start from 1 meter below the pile top, slowly lift and rotate to spray, and stop the shotcrete operation after it exceeds the designed pile top by 0.5 meters.

[0015] Compared with the prior art, the present invention adopting the above technical solution has the following outstanding features:

[0016] In the water-rich quicksand layer, the construction principle of top-down rotary spraying and grouting combined with low-pressure grouting method is adopted to effectively control the phenomenon of hole collapse, drill stuck and drill buried. This method has the characteristics of short construction period, high safety performance, maximum economic benefit, saving wall protection materials and high pile quality. It is suitable for various types of highly active permeable layers and is used in urban construction with high environmental protection requirements.

[0017] Preferably, a further technical solution of the present invention is:

[0018] In step five, the water-cement ratio of the slurry is between 0.8:1-1.2:1, the slurry pressure is between 0.5-2Mpa, and the water pressure is between 0.5-2Mpa.

[0019] In step six, the water-cement ratio of the slurry is between 1:0.5-1:1.2, the Baume degree is between 35-40be', the slurry pressure is between 25-35Mpa, the water pressure is between 20-35Mpa, the air pressure is between 0.5-1Mpa, and the rotation speed is between 15-25r / min.

[0020] During the jet grouting in step seven, the slurry pressure is between 30-40 MPa, the water pressure is between 25-40 MPa, the air pressure is between 0.5-1 MPa, and the lifting speed is between 5-20 cm / min.

[0021] In step eight, the lifting speed of the rotary jet drill is between 30-50 cm / min, and the rotation speed is between 5-10 r / min. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of a triple-tube high-pressure rotary spraying machine in an embodiment of the present invention;

[0023] Figure 2 It is a structural schematic diagram of a drill rod of a rotary jet grouting machine in an embodiment of the present invention;

[0024] Figure 3 Schematic diagram of the structure of a shotcrete drill bit in an embodiment of the present invention;

[0025] Figure 4 It is a structural schematic diagram of a slurry stirring system in an embodiment of the present invention;

[0026] Figure 5 It is a structural schematic diagram of a compressed air system in an embodiment of the present invention;

[0027] Figure 6 It is a structural schematic diagram of a water storage system in an embodiment of the present invention;

[0028] Figure 7 A schematic diagram of the structure of a power generation system in an embodiment of the present invention;

[0029] Figure 8 It is a construction process flow chart of the present invention;

[0030] Fig. 9 This is a structural diagram of the equipment when it is assembled and tested during the construction process using this construction method;

[0031] Fig.10 This is a structural diagram of the drilling and spraying integrated construction method used in the construction process of this construction method;

[0032] Fig.11 This is a structural schematic diagram of the use of the "reverse injection method" in the water-rich quicksand layer during the construction process of this construction method;

[0033] Fig.12 This is a structural schematic diagram of the combination of the "reverse spraying method" and the drilling and spraying integrated construction method during the construction process of this construction method;

[0034] Fig.13 This is a structural schematic diagram of rotary lifting and low-pressure grouting during the construction process using this construction method;

[0035] Fig.14 This is a structural schematic diagram of the completion of the rotary grouting during the construction process using this construction method;

[0036] The markings in the figure are: triple-tube high-pressure jet grouting machine 1, jet grouting machine drill rod 2, shotcrete drill bit 3, slurry mixing system 4, compressed air system 5, water storage system 6, and power generation system 7. DETAILED DESCRIPTION

[0037] The present invention will be further described below in conjunction with embodiments, the purpose of which is only to provide a better understanding of the content of the present invention. Therefore, the examples given do not limit the protection scope of the present invention.

[0038] A construction method of high-pressure jet grouting piles in a water-rich sand layer includes the following steps:

[0039] Step 1: preset a triple-tube high-pressure rotary jet machine 1, a rotary jet machine drill rod 2 and a shotcrete drill bit 3 and assemble them. The model of the triple-tube high-pressure rotary jet machine 1 is Juqiang XPL-150, with a drilling diameter of 400-1000mm, a maximum drilling depth of 150000mm, a rotation speed of 0-266m, and a power head speed of 0-278r / min. The rotary jet machine drill rod 2 has a diameter of 89mm and a length of 3000mm per section. The shotcrete drill bit 3 is made of three-wing diamond, with a diameter of 89mm and 4 nozzles, of which the upper two are water and gas nozzles, and the lower two are slurry nozzles with a nozzle diameter of 2-3.5mm. The axes of the water and gas nozzles are arranged in the horizontal direction, and the axis of the slurry nozzle is inclined downward by 10° in the horizontal direction. A slurry automatic mixer is preset and equipped with a high-pressure grouting pump to form a slurry mixing system System 4, the model of the automatic slurry mixer is ZJ2000L, the model of the high-pressure grouting pump is GZB-40C, the rated power is 90kw, the rated pressure is 35-42Mpa, the preset air compressor is equipped with an air storage tank to form a compressed air system 5, the air compressor has a rated power of 30kw, a volume flow of 5m³ / min, and an exhaust pressure of 0.8Mpa, the maximum allowable working pressure of the air storage tank is 0.84Mpa, and the volume is 1m³, the preset clean water tank is equipped with a high-pressure clean water pump to form a water storage system 6, the clean water tank capacity is 50L, the high-pressure clean water pump flow is 50m³ / h, and the rated power is 15kw, the preset generator set is equipped with a distribution box to form a power generation system 7, the generator set uses a power of 400kw, which can meet the simultaneous operation of two sets of equipment, 2 secondary distribution boxes and 6 tertiary distribution boxes.

[0040] Step 2: After the triple-tube high-pressure jet grouting machine 1, the jet grouting machine drill rod 2 and the shotcrete drill bit 3 are assembled, the verticality of the jet grouting machine drill rod 2 is debugged.

[0041] Step 3: Install the slurry mixing system 4, compressed air system 5, water storage system 6 and power generation system 7 on the triple-tube high-pressure jet spraying machine 1 to check whether the whole system is operating normally.

[0042] Step 4: Before construction, conduct a test spray on the ground to check whether there are any leaks in the air pipe, whether there are any leaks in the water pipe, and check the pressure of the grouting pump.

[0043] Step 5: During construction, the drilling and spraying method is preferred. The spraying drill bit 3 first sprays cement slurry and then drills to make holes. After drilling, gas and water are sprayed. The slurry water-cement ratio is between 0.8:1-1.2:1, the slurry pressure is between 0.5-2Mpa, and the water pressure is between 0.5-2Mpa. The drilling and spraying method is easy to form holes and avoids blockage of the nozzle by the soil.

[0044] Step 6: When drilling into the water-rich flowing sand layer, the slurry nozzle of the shotcrete drill bit 3 is tilted downward at an angle of 10°, and the slurry is sprayed from top to bottom in a rotary spraying manner. This is the "reverse spraying method", and cement + water glass double slurry is used to make slurry. The slurry water-cement ratio is between 1:0.5-1:1.2, the Baume degree is between 35-40be', the slurry pressure is between 25-35Mpa, the water pressure is between 20-35Mpa, the air pressure is between 0.5-1Mpa, and the rotation speed is between 15-25r / min. The double slurry can not only achieve a good water-stopping reinforcement effect, but its rapid coagulation can be mixed with the sand layer to play a stabilizing role. The water glass stone has high strength and low impact on the water quality environment. This method can well avoid the phenomenon of drill pipe jamming and burying the drill in the sand layer. The gas is used to cut the flowing sand soil, and the double slurry is used for filling.

[0045] Step 7: After penetrating the water-rich sand layer, continue the construction using the integrated drilling and spraying method in step 5 until the designed pile bottom is drilled, and slurry, water and air are delivered in time. After reaching the designed spraying pressure, perform spray grouting. Rotate, lift and spray at the same time, and spray grouting from bottom to top. Rotate and lift continuously without interruption. During spray grouting, the slurry pressure is between 30-40Mpa, the water pressure is between 25-40Mpa, the air pressure is between 0.5-1Mpa, and the lifting speed is between 5-20cm / min.

[0046] Step 8: When lifting to the double-liquid slurry water-rich sand layer where grouting has been completed, switch to low-pressure grouting method, slowly lift the rotary jet drill rod 2 at this stratum position, the lifting speed of the rotary jet drill is between 30-50cm / min, the rotation speed is between 5-10r / min, the shotcrete drill bit 3 only sprays cement slurry, and does not spray gas and water. The low-pressure grouting method can fill the slurry loss and mud-sand interlayer caused by hole making, and solve the common problems such as poor pile quality and low pile body strength.

[0047] Step nine: When the shotcrete drill bit 3 is lifted to a position close to the designed pile top, start from 1 meter below the pile top, slowly lift and rotary spray, and stop the shotcrete operation after it exceeds the designed pile top by 0.5 meters. After the rotary spray machine drill rod 2 is lifted to the ground, all machinery and equipment are rinsed with clean water to prevent solidification and blockage.

[0048] In the water-rich quicksand layer, the construction principle of top-down rotary spraying and grouting combined with low-pressure grouting method is adopted to effectively control the phenomenon of hole collapse, drill stuck and drill buried. This method has the characteristics of short construction period, high safety performance, maximum economic benefit, saving wall protection materials and high pile quality. It is suitable for various types of highly active permeable layers and is used in urban construction with high environmental protection requirements.

[0049] The above description is only a preferred feasible embodiment of the present invention, and does not limit the scope of rights of the present invention. All equivalent changes made using the contents of the present specification and its drawings are included in the scope of rights of the present invention.

Claims

1. A construction method of high-pressure jet grouting piles in water-rich sand layers, characterized in that: The steps include: Step 1: Preset and assemble a triple-tube high-pressure jet grouting machine, a jet grouting machine drill rod and a shotcrete drill bit. The axis of the slurry nozzle of the shotcrete drill bit is tilted downward in the horizontal direction. Preset an automatic slurry mixer and equip it with a high-pressure grouting pump to form a slurry mixing system. Preset an air compressor and equip it with an air storage tank to form a compressed air system. Preset a clean water tank and equip it with a high-pressure clean water pump to form a water storage system. Preset a generator set and equip it with a distribution box to form a power generation system. Step 2: After the triple-tube high-pressure jet grouting machine, the jet grouting machine drill rod and the shotcrete drill bit are assembled, the verticality of the jet grouting machine drill rod is debugged; Step 3: Install the slurry mixing system, compressed air system, water storage system and power generation system on the triple-tube high-pressure jet spraying machine, and check whether the whole system is working normally; Step 4: Before construction, test spray on the ground to check whether there is air leakage in the air pipe, water leakage in the water pipe, and check the pressure of the grouting pump; Step 5: The drilling and spraying method is the first choice for construction. The spraying drill first sprays cement slurry and then drills down to make holes. After drilling, gas and water are sprayed; Step 6: When drilling into the water-rich flowing sand layer, the slurry nozzle of the grouting drill bit is tilted downward, and the grouting is sprayed from top to bottom. The cement + water glass double slurry is used to make slurry, and the gas is used to cut the flowing sand soil, and the double slurry is used to fill; Step 7: After penetrating the water-rich sand layer, continue the construction by using the integrated drilling and spraying method in step 5 until the designed pile bottom is drilled, and the slurry, water and air are delivered in time. After reaching the designed spraying pressure, spray grouting is carried out, rotating, lifting and spraying at the same time, spraying grouting from bottom to top, and the rotation and lifting are continuous and uninterrupted; Step 8: When the grouting is completed in the double-liquid slurry water-rich flowing sand layer, the low-pressure grouting method is used. The rotary jet drill rod is slowly lifted at this formation position. The grouting drill bit only sprays cement slurry without spraying gas and water. Step 9: When the shotcrete drill bit is lifted close to the designed pile top, start from 1 meter below the pile top, slowly lift and rotate to spray, and stop the shotcrete operation after it exceeds the designed pile top by 0.5 meters.

2. The construction method of high-pressure jet grouting piles in water-rich sand layer geology according to claim 1 is characterized by: In step five, the water-cement ratio of the slurry is between 0.8:1-1.2:1, the slurry pressure is between 0.5-2Mpa, and the water pressure is between 0.5-2Mpa.

3. The construction method of high-pressure jet grouting piles in water-rich sand layer geology according to claim 1 is characterized by: In step six, the water-cement ratio of the slurry is between 1:0.5-1:1.2, the Baume degree is between 35-40°Bé, the slurry pressure is between 25-35Mpa, the water pressure is between 20-35Mpa, the air pressure is between 0.5-1Mpa, and the rotation speed is between 15-25r / min.

4. The construction method of high-pressure jet grouting piles in water-rich sand layer geology according to claim 1 is characterized in that: During the jet grouting in step seven, the slurry pressure is between 30-40 MPa, the water pressure is between 25-40 MPa, the air pressure is between 0.5-1 MPa, and the lifting speed is between 5-20 cm / min.

5. The construction method of high-pressure jet grouting piles in water-rich sand layer geology according to claim 1 is characterized in that: In step eight, the lifting speed of the rotary jet drill is between 30-50 cm / min, and the rotation speed is between 5-10 r / min.

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