Vacuum degree measuring head embedding method in vacuum preloading method

Abstract

The invention discloses a method for embedding a vacuum degree measuring head in a vacuum preloading method. The method comprises the following steps of: drilling at an embedding position of the vacuum degree measuring head; a casing pipe is put in after drilling; air-dried clay balls are adopted to plug the bottom of the casing pipe and are compacted; the vacuum degree measuring head needing to be embedded deepest is put into the preset depth according to the design requirement, then air-dried clay balls are put into the vacuum degree measuring head, plugging and compacting are conducted till the vacuum degree measuring head is 100-300 mm below the preset depth of the second vacuum degree measuring head, and then the second vacuum degree measuring head is put into the vacuum degree measuring head; the operation is repeated in sequence until all the vacuum degree measuring heads are embedded; switching hoses of the vacuum degree measuring heads with different embedding depths are connected into a vacuum degree pressure gauge, and then the vacuum degree pressure gauge is connected with a vacuum degree tester through an electric wire; and the embedded vacuum degree measuring head is tested. The vacuum degree measuring head can be effectively guaranteed to be intact, the deep vacuum degree measuring head can be embedded in the inner side of the sleeve in advance and is firm and stable, and the vacuum degree measuring accuracy is guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of geotechnical engineering, in particular to a method for burying a vacuum degree measuring head in a vacuum preloading method. Background Art

[0002] Recently deposited soils such as silt and backfill have engineering characteristics such as high water content, low strength, and under-consolidation. Using vacuum preloading method for foundation treatment is an effective way to reduce soil water content, enhance soil strength, and accelerate soil consolidation. This method is widely used in coastal, riverside and lakeside areas.

[0003] During the construction process of vacuum preloading method, monitoring the vacuum pressure under the membrane and at different depths of the treated soil is a necessary task to dynamically guide the construction. The buried quality of vacuum probes at different depths is an important process to ensure vacuum monitoring. Summary of the invention

[0004] The technical problem to be solved by the present invention is to address the deficiencies in the prior art and to provide a method for burying a vacuum probe in a vacuum preloading method, which can standardize the method for burying a vacuum probe, effectively ensure the integrity of the vacuum probe, and ensure that the vacuum probe does not become blocked, so that the deep vacuum probe can be buried in the inner side of the casing in advance and firmly and stably, thereby ensuring the accuracy of vacuum measurement.

[0005] The technical problem to be solved by the present invention is achieved by the following technical solution. The present invention is a method for embedding a vacuum probe in a vacuum preloading method, and the steps of the method are as follows: (1) Drill a hole at the location where the vacuum probe is buried; (2) After drilling, insert the casing and clean the hole inside the casing until the water circulates and becomes clear; (3) Use air-dried clay balls to seal the bottom of the casing and compact it; (4) According to the design requirements, place the vacuum probe that needs to be buried the deepest to the predetermined depth, then put in air-dried clay balls for sealing and compaction until the second vacuum probe is 100-300 mm below the predetermined depth, and then place the second vacuum probe; (5) Repeat step (4) until all vacuum probes are buried; (6) Connect the adapter hoses of vacuum probes with different burial depths to the vacuum pressure gauge, and then connect the vacuum pressure gauge to the vacuum tester through wires; (7) Test the buried vacuum gauges. If some of the vacuum gauges are abnormal, drill additional holes at a distance of 400 to 600 mm from the buried position of the vacuum gauges and re-bury them.

[0006] The technical problem to be solved by the present invention can be further achieved by the following technical scheme. For the method for burying a vacuum probe in the vacuum preloading method described above, in step (1), the hole is drilled by an engineering drill rig through a mud wall core tube rotary method, the drill bit diameter is 110 mm or 127 mm, and the hole is drilled at one time to a position 200 mm below the deepest buried vacuum probe.

[0007] The technical problem to be solved by the present invention can be further achieved by the following technical solution. For the method for embedding a vacuum probe in the vacuum preloading method described above, in step (2), the inserted casing is a casing with a diameter of 110 mm or 127 mm.

[0008] The technical problem to be solved by the present invention can be further achieved by the following technical solution. For the vacuum probe embedding method in the vacuum preloading method described above, in steps (3) and (4), the air-dried clay ball has a clay content greater than 30%, a plasticity index greater than 17, and a diameter of 20 to 25 mm.

[0009] The technical problem to be solved by the present invention can be further achieved by the following technical solution. For the method for embedding the vacuum probe in the vacuum preloading method described above, in steps (3) and (4), compaction is carried out by a hammering method using a compactor.

[0010] The technical problem to be solved by the present invention can also be further achieved by the following technical scheme. For the vacuum probe embedding method in the vacuum preloading method described above, in this method, the vacuum probe has a diameter of 30 mm and a length of 130 mm. A sieve hole is opened in the middle 90 mm position. The sieve holes are arranged in a plum blossom shape. The sieve hole diameter is 2 mm, and the hole area accounts for 30.6%~31.0%.

[0011] The technical problem to be solved by the present invention can be further achieved through the following technical scheme. For the vacuum probe burying method in the vacuum preloading method described above, in this method, a vacuum probe protection device is used to protect the vacuum probe before burying. The vacuum probe protection device includes a UPVC filter tube, a UPVC pipe head cap, medium-coarse sand, and a mesh non-woven geotextile.

[0012] The technical problem to be solved by the present invention can also be further achieved by the following technical scheme. For the above-mentioned method for burying the vacuum probe in the vacuum preloading method, the UPVC filter tube is a UPVC filter tube with a diameter of 60 mm and a length of 200 mm. The sieve holes are opened at 130 mm in the middle of the UPVC filter tube. The sieve holes are arranged in a plum blossom shape. The sieve holes include two types of apertures: 6 mm and 2 mm. The hole spacing of the opened sieve holes along the circumference of the UPVC filter tube in the horizontal plane is 15 mm, and the hole spacing along the vertical direction is 20 mm. The 6 mm sieve holes and the 2 mm sieve holes are distributed alternately, and the hole area accounts for 4.0% to 4.4%; The UPVC pipe cap is a UPVC pipe cap with a diameter of 75 mm, an outer diameter of 75 mm, an inner diameter of 61 mm, a length of 35 mm, and a 15 mm inner thread; The medium-coarse sand is medium-coarse sand with a particle size greater than 0.25 mm, the mesh includes 200 mesh mesh and 300 mesh mesh, and the non-woven geotextile is 200g / m 2 Non-woven geotextile.

[0013] The technical problem to be solved by the present invention can be further achieved by the following technical solutions. For the method of burying the vacuum probe in the vacuum preloading method described above, the method of installing the vacuum probe protection device is as follows: (1) Connect the vacuum probe to the adapter hose and check to ensure there is no air leakage at the joint; (2) Wrap the vacuum probe with a layer of 300 mesh gauze, tie it tightly with cotton thread at the upper and lower parts, and then wrap the outer layer of the vacuum probe with a layer of 200g / m 2 Non-woven geotextile, and fasten it with plastic tie bands at the upper and lower parts; (3) Wrap the UPVC filter tube with a layer of 200 mesh gauze, tie it tightly with cotton thread at the upper and lower parts, and wrap the outer layer with a layer of 200g / m 2 The non-woven geotextile is fastened with plastic tie bands at the upper and lower parts; (4) Prepare two UPVC pipe caps, drill a 15mm diameter hole in the middle of one of the UPVC pipe caps and insert the adapter hose, then transfer the other UPVC pipe cap to the bottom of the UPVC filter tube and tighten it to place it vertically; (5) Place the wrapped vacuum probe into the UPVC filter tube, fill the UPVC filter tube with medium-coarse sand with a particle size greater than 0.25 mm, and then tighten the UPVC pipe cap with a round hole drilled into the top of the UPVC filter tube; (6) Seal the joint between the adapter hose and the UPVC pipe cap with sealant; (7) The deep vacuum probe with a protective device is buried inside the casing at a specified depth; (8) Effectively connect the vacuum probe, adapter hose, vacuum pressure gauge, wires and vacuum tester.

[0014] Compared with the prior art, the present invention fills the gap in the method of burying a deep vacuum pressure gauge in the vacuum preloading method, effectively ensuring that the vacuum probe is not blocked or filled with fine particles of soil during the entire vacuum preloading construction period, thereby ensuring the accuracy of deep vacuum measurement of the soil. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A schematic diagram of the structure of the vacuum measuring head of the present invention; Figure 2 It is a structural schematic diagram of the UPVC filter tube of the present invention; Figure 3 It is a structural schematic diagram of the UPVC pipe head cap of the present invention; DETAILED DESCRIPTION

[0016] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0017] Reference Figures 1 to 3 , a method for burying a vacuum probe 1 in a vacuum preloading method, standardizing the method for burying the vacuum probe 1, effectively ensuring the integrity of the vacuum probe 1, and ensuring that the vacuum probe 1 does not cause clogging, so that the deep vacuum probe 1 is buried in the inner side of the casing in advance and is firm and stable, and ensuring the accuracy of vacuum measurement; In order to fill the technical gap of missing specifications, the present invention proposes vacuum measurement technical requirements, and in order to standardize the embedding method of the vacuum probe 1, the present invention provides effective embedding steps. In order to ensure that the vacuum probe 1 does not produce clogging, the present invention provides a vacuum probe 1 protection device with technical advantages, specifically: 1. Technical requirements of the present invention: (1) The vacuum measuring instrument includes a vacuum measuring head 1, a connecting hose 2, a vacuum negative pressure gauge, electric wires and a vacuum tester; (2) To improve the accuracy of vacuum numerical measurement, vacuum measuring instruments are evenly placed around and in the center of the vacuum preloading soft foundation treatment area; (3) To avoid interference with the data when the vacuum pump is working, a reasonable distance needs to be maintained between the vacuum probe 1 and the vacuum pump during the installation of the vacuum measuring instrument; (4) The vacuum probe cannot be placed directly in the casing; (5) Deep vacuum degree measuring instruments should be buried in the road area within the vacuum preloading treatment site; (6) The deep vacuum probe 1 needs to be buried inside the casing in advance and firmly fixed.

[0018] 2. The embedding steps of the present invention: (1) Use an engineering drilling rig (such as GXY~1) to drill through the mud wall core tube rotary method, with a drill bit diameter of Φ110mm or Φ127mm, and drill a hole to 200mm below the deepest buried vacuum probe 1 at one time; (2) To prevent shrinkage or hole collapse, quickly run a Φ110mm or Φ127mm diameter casing and use a smaller diameter drill to clean the hole in the casing. The operation can be stopped only after the clean water is circulated and observed to be clear. (3) For plugging, air-dried clay balls with a clay content greater than 30%, a plasticity index greater than 17, and a diameter of 20 to 25 mm are used; compaction is carried out using a hammering method; (4) According to the design requirements, the deepest buried vacuum probe 1 is placed at a predetermined depth, and air-dried clay balls of about 100 mm to 150 mm are put in for compaction, and plugging is performed from bottom to top. The compaction is stopped when the second vacuum probe 1 is 200 mm below the predetermined depth, and the second vacuum probe 1 is placed in. (4) Repeat step (3) from top to bottom until all the clearance probes are buried; (5) Connect the vacuum probes 1 and the upper part of the adapter hose 2 with different burial depths to the vacuum pressure gauge, and connect the vacuum pressure gauge to the vacuum tester through wires; (6) Test the buried vacuum test instrument. If some vacuum probes are abnormal, drill additional holes about 500 mm away from the hole and bury them.

[0019] 3. Vacuum probe 1 protection device In order to effectively protect the vacuum measuring head 1, the present invention provides a vacuum measuring head 1 protection device, which mainly consists of 5 parts: (1) UPVC filter tube 3 with a diameter of Φ60 mm and a length of 200 mm; (2) UPVC pipe head with a diameter of Φ75 mm; (3) Medium-coarse sand with a particle size greater than 0.25 mm; (4) 200 mesh and 300 mesh mesh; (5) 200g / m 2 Non-woven geotextiles; In actual application, the vacuum probe 1 has a diameter of Φ30 mm and a length of 130 mm. The sieve holes are arranged in a plum blossom shape. The sieve hole diameter is 2 mm, and the percentage of hole area is about 30.6%~31.0%, preferably 30.8%; see the attached Figure 1 ; The UPVC filter tube 3 has a diameter of Φ60mm and a length of 200mm. The sieve holes are arranged in a plum blossom shape. The sieve holes include two types of apertures: 6mm and 2mm. The sieve holes have a hole spacing of 15mm in the horizontal plane and 20mm in the vertical direction along the circumference of the UPVC filter tube. The 6mm sieve holes and the 2mm sieve holes are distributed alternately. The hole area accounts for 4.0%~4.4%, preferably 4.2%; see the attached Figure 2 ; The UPVC pipe cap 4 has an outer diameter of Φ75mm, an inner diameter of Φ61mm, a pipe head length of 35mm, and an inner thread of 15mm, and is used for screwing onto the UPVC filter pipe 3; see the attached Figure 3 .

[0020] The installation method of the vacuum measuring head 1 protection device is as follows: (1) Connect the vacuum measuring head 1 and the adapter hose 2, and check to ensure that there is no air leakage at the joint; (2) Wrap the vacuum probe 1 with a layer of 300 mesh gauze, tie it tightly with cotton thread at the upper and lower parts, and wrap the outer layer of the vacuum probe 1 with a layer of 200g / m 2 The non-woven geotextile is fastened with plastic tie bands at the upper and lower parts; (3) Wrap the UPVC filter tube 3 with a layer of 200 mesh gauze, tie it tightly with cotton thread at the upper and lower parts, and wrap it with a layer of 200g / m 2 The non-woven geotextile is fastened with plastic tie bands at the upper and lower parts; (4) Prepare two UPVC pipe caps 4, drill a 15 mm diameter hole in the middle of one of the UPVC pipe caps 4 and insert the adapter hose 2, then transfer the other UPVC pipe cap 4 to the bottom of the UPVC filter tube 3 and tighten it to place it vertically; (5) Place the wrapped vacuum measuring head 1 into the UPVC filter tube 3, fill the UPVC filter tube 3 with medium-coarse sand with a particle size greater than 0.25 mm, and then tighten the UPVC pipe cap 4 with a round hole drilled into the top of the UPVC filter tube 3; (6) Seal the joint between the adapter hose 2 and the UPVC pipe cap 4 with sealant; (7) burying the deep vacuum probe 1 with a protective device inside the casing at a specified depth; (8) Effectively connect the vacuum measuring head 1, the adapter hose 2, the vacuum negative pressure gauge, the wires and the vacuum tester.

[0021] The method for burying the vacuum probe 1 in the vacuum preloading method provided by the present invention fills the gap in the method for burying the deep vacuum pressure gauge in the vacuum preloading method, effectively ensuring that the vacuum probe 1 is not blocked or filled with fine particles of soil during the entire vacuum preloading construction period, thereby ensuring the accuracy of deep vacuum measurement of the soil.

Claims

1. A method for embedding a vacuum probe in a vacuum preloading method, characterized in that: The steps of this method are as follows: (1) Drill a hole at the location where the vacuum probe is buried; (2) After drilling, insert the casing and clean the hole inside the casing until the water circulates and becomes clear; (3) Use air-dried clay balls to seal the bottom of the casing and compact it; (4) According to the design requirements, place the vacuum probe that needs to be buried the deepest to the predetermined depth, then put in air-dried clay balls for sealing and compaction until the second vacuum probe is 100-300 mm below the predetermined depth, and then place the second vacuum probe; (5) Repeat step (4) until all vacuum probes are buried; (6) Connect the adapter hoses of vacuum probes with different burial depths to the vacuum pressure gauge, and then connect the vacuum pressure gauge to the vacuum tester through wires; (7) Test the buried vacuum gauges. If some of the vacuum gauges are abnormal, drill additional holes at a distance of 400 to 600 mm from the buried position of the vacuum gauges and re-bury them.

2. The method for embedding a vacuum probe in a vacuum preloading method according to claim 1, characterized in that: In step (1), the hole is drilled by a construction drilling rig using a mud-walled core tube rotary method, with a drill bit diameter of 110 mm or 127 mm, and the hole is drilled in one go to a position 200 mm below the deepest buried vacuum probe.

3. The method for embedding a vacuum probe in a vacuum preloading method according to claim 1, characterized in that: In step (2), the inserted casing has a diameter of 110 mm or 127 mm.

4. The method for embedding a vacuum probe in a vacuum preloading method according to claim 1, characterized in that: In steps (3) and (4), the air-dried clay balls have a clay content greater than 30%, a plasticity index greater than 17, and a diameter of 20 to 25 mm.

5. The method for embedding a vacuum probe in a vacuum preloading method according to claim 1 or 4, characterized in that: In steps (3) and (4), compaction is performed by hammering with a compactor.

6. The method for embedding a vacuum probe in a vacuum preloading method according to claim 1, characterized in that: In this method, the vacuum measuring head has a diameter of 30 mm and a length of 130 mm. A sieve hole is opened at the middle 90 mm position. The sieve holes are arranged in a plum blossom shape. The sieve hole diameter is 2 mm, and the hole area accounts for 30.6%~31.0%.

7. The method for embedding a vacuum probe in a vacuum preloading method according to claim 1 or 6, characterized in that: In the method, a vacuum probe protection device is used to protect the vacuum probe before burying, and the vacuum probe protection device includes a UPVC filter pipe, a UPVC pipe head cap, medium-coarse sand, and a mesh non-woven geotextile.

8. The method for embedding a vacuum probe in a vacuum preloading method according to claim 7, characterized in that: The UPVC filter tube is a UPVC filter tube with a diameter of 60 mm and a length of 200 mm. A sieve hole is provided at 130 mm in the middle of the UPVC filter tube. The sieve holes are arranged in a plum blossom shape. The sieve holes include two types of apertures: 6 mm and 2 mm. The hole spacing of the sieve holes along the circumference of the UPVC filter tube in the horizontal plane is 15 mm, and the hole spacing along the vertical direction is 20 mm. The 6 mm sieve holes and the 2 mm sieve holes are distributed at intervals, and the hole area accounts for 4.0% to 4.4%; The UPVC pipe cap is a UPVC pipe cap with a diameter of 75 mm, an outer diameter of 75 mm, an inner diameter of 61 mm, a length of 35 mm, and a 15 mm inner thread; The medium-coarse sand is medium-coarse sand with a particle size greater than 0.25 mm, the mesh includes 200 mesh mesh and 300 mesh mesh, and the non-woven geotextile is 200g / m 2 Non-woven geotextile.

9. The method for embedding a vacuum probe in a vacuum preloading method according to claim 7, characterized in that: The installation method of the vacuum probe protection device is as follows: (1) Connect the vacuum probe to the adapter hose and check to ensure there is no air leakage at the joint; (2) Wrap the vacuum probe with a layer of 300 mesh gauze, tie it tightly with cotton thread at the upper and lower parts, and then wrap the outer layer of the vacuum probe with a layer of 200g / m 2 Non-woven geotextile, and fasten it with plastic tie bands at the upper and lower parts; (3) Wrap the UPVC filter tube with a layer of 200 mesh gauze, tie it tightly with cotton thread at the upper and lower parts, and wrap the outer layer with a layer of 200g / m 2 The non-woven geotextile is fastened with plastic tie bands at the upper and lower parts; (4) Prepare two UPVC pipe caps, drill a 15mm diameter hole in the middle of one of the UPVC pipe caps and insert the adapter hose, then transfer the other UPVC pipe cap to the bottom of the UPVC filter tube and tighten it to place it vertically; (5) Place the wrapped vacuum probe into the UPVC filter tube, fill the UPVC filter tube with medium-coarse sand with a particle size greater than 0.25 mm, and then tighten the UPVC pipe cap with a round hole drilled into the top of the UPVC filter tube; (6) Seal the joint between the adapter hose and the UPVC pipe cap with sealant; (7) The deep vacuum probe with a protective device is buried inside the casing at a specified depth; (8) Effectively connect the vacuum probe, adapter hose, vacuum pressure gauge, wires and vacuum tester.

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