Cross-hole seismic tomography for detecting diaphragm walls in boulder stratum and construction method

Abstract

The present invention relates to a method for detecting a diaphragm wall in a boulder stratum by cross-hole seismic tomography and a construction method thereof, which includes the following steps: boulder detection, pre-decomposition punching of beaded boulder stratum by blasting, pressure relief and air release covering at the top of the blasting hole, and cleaning the groove with a square hammer brush. The beneficial effects of the present invention are as follows: By using cross-hole seismic tomography equipment, a dense detection path is formed in the measurement area, and then the distribution of boulders in the measurement area is calculated and deduced. It has the characteristics of good reliability, strong intuitiveness and high accuracy, ensuring efficient and high-quality diaphragm wall construction; after detecting the position information of boulders within the range of the diaphragm wall, blasting hole drilling construction is carried out, and then explosives are loaded according to the intermittent method, that is, explosives are only placed at the boulder positions, so as to achieve the purpose of pre-blasting decomposition, greatly improving the grooving progress, reducing the construction difficulty, and effectively ensuring the stability of the groove wall.

Description

Technical Field

[0001] The invention belongs to the field of diaphragm wall construction, and particularly relates to a diaphragm wall in a boulder stratum detected by seismic wave crosshole tomography and a construction method thereof. Background Technique

[0002] With the development of urban construction, the utilization of urban underground space has received increasing attention. During the development and construction of urban underground projects, the diaphragm wall, as one of the forms of deep foundation pit support, is widely used because of its good anti-seepage performance, large stiffness, and high safety and reliability.

[0003] However, the construction of diaphragm walls in complex boulder strata is difficult, so it is difficult to ensure the construction progress and quality. When constructing the diaphragm wall, problems such as ground settlement, difficult grooving, and easy collapse brought by boulders during the construction process have always been the key factors restricting the grooving of the diaphragm wall. At the same time, due to the dense urban buildings, there are high requirements for vibration control and displacement settlement during the construction process. The traditional diaphragm wall construction technology has been difficult to adapt to such complex geological and hydrological conditions, so higher requirements are put forward for diaphragm wall construction.

[0004] Therefore, how to accurately explore boulder information and explore efficient boulder treatment technologies is of great significance. Summary of the Invention

[0005] The purpose of the invention is to overcome the deficiencies in the prior art and provide a diaphragm wall in a boulder stratum detected by seismic wave crosshole tomography and a construction method thereof.

[0006] The construction method of such a diaphragm wall in a boulder stratum detected by seismic wave crosshole tomography includes the following construction steps:

[0007] S1. Boulder detection: Bury PE pipes, and form detection paths in the measurement area through the fan-shaped penetration method of one-shot multi-receiving to detect the positions of boulders;

[0008] S2. Blasting and pre-decomposing and punching in the beaded boulder stratum: Arrange blasting holes and bury PVC pipes with sealed bottoms, and place explosives at the positions corresponding to the boulders in the PVC pipes;

[0009] S3. Pressure relief and gas discharge covering at the top of the blasting hole: Seal the PVC pipe, install a pressure relief and gas discharge covering device, and perform blasting operations after applying pressure above the pressure relief and gas discharge covering device;

[0010] S4. Square hammer brushing and grooving cleaning: Scrape and clean the sundries on the I-beam at the groove section joint, and pour the diaphragm wall.

[0011] Preferably, step S1 includes:

[0012] S1.1. Drill holes on the ground at the construction position and bury PE pipes;

[0013] S1.2. Place the transmitter and receiver into the PE pipes arranged on both sides of the boulder respectively to form a detection path in the measurement area;

[0014] S1.3. Connect the transmitter and receiver to the transmitter instrument and receiver instrument respectively, and connect them to the terminal computer through signal lines to obtain measurement data;

[0015] S1.4. Analyze the measurement data to detect the location of the boulder.

[0016] Preferably, the PE pipe is higher than the ground; the bottom of the PE pipe is completely sealed with a bottom sealing cover, and a top sealing cover is provided at the top of the PE pipe, and a signal line installation position is reserved on the top sealing cover.

[0017] Preferably, step S2 includes:

[0018] S2.1. Drill a hole in the boulder as a blasting hole;

[0019] S2.2. Place a PVC pipe with a bottom sealing cover at the bottom of the pipe into the blasting hole;

[0020] S2.3. Install explosives in the PVC pipe according to the detected position of the boulder.

[0021] Preferably, for large boulders with a width greater than the thickness of the diaphragm wall, the blasting holes are arranged in a plum blossom shape; for small boulders with a width less than the thickness of the diaphragm wall, the blasting holes are arranged in a single row inside and empty holes are arranged on both sides of the small boulder.

[0022] Preferably, step S3 includes:

[0023] S3.1. Lead the detonating fuse out of the orifice of the blasting hole at the upper part of the PVC pipe, and use the stuffing to block the upper cavity of the PVC pipe;

[0024] S3.2. Set up a bamboo cover plate at the ground of the orifice, and install a pressure relief and air release covering device above the bamboo cover plate; press the steel plate of the pressure relief and air release covering device by carrying sandbags.

[0025] Preferably, the pressure relief and air release covering device includes a steel plate, a steel pipe, a top cover and a connector. A hole is opened in the center of the steel plate to connect the steel pipe, and the top of the steel pipe is connected to the top cover through the connector, and the sandbag is installed on the steel plate.

[0026] Preferably, the blocking height of the stuffing for blocking the upper cavity of the PVC pipe is controlled at 4 - 5 m.

[0027] Preferably, step S4 includes:

[0028] S4.1. Use a lifting device to lift the square hammer wall scrubber with the help of a lifting ring; one end of the square hammer wall scrubber is provided with an end mud scraper, and the other end is provided with a wire brush.

[0029] S4.2. Use the end mud scraper to brush the I-beam joint up and down.

[0030] S4.3. Use the end with the wire brush to clean the inner wall of the I-beam joint.

[0031] The cross-hole seismic tomography detection of boulders in the diaphragm wall is obtained by any of the above methods.

[0032] The beneficial effects of the present invention are as follows:

[0033] 1) The present invention proposes a cross-hole seismic tomography scanning boulder detection technology. By using a cross-hole seismic tomography device, a dense detection path is formed in the measurement area, and then the distribution of boulders in the measurement area is calculated and deduced. It has the characteristics of good reliability, strong intuitiveness and high accuracy, ensuring efficient and high-quality diaphragm wall construction.

[0034] 2) The present invention proposes a pre-explosion decomposition punching technology for beaded boulder formations. After detecting the position information of boulders within the range of the diaphragm wall, drilling construction of blasting holes is carried out, and then explosives are loaded according to the intermittent method, that is, explosives are only placed at the positions of boulders, so as to achieve the purpose of pre-explosion decomposition, greatly improving the grooving progress, reducing the construction difficulty, and effectively ensuring the stability of the grooved wall.

[0035] 3) The present invention proposes a pressure relief and air release covering technology for the top of the blasting hole. Install a bamboo cover plate at the top of the blasting hole, and use sandbags to compact and install a pressure relief and air release covering device on the upper part, so that the hole can relieve pressure and ventilate while filtering most of the ejected stuffing. The stuffing that cannot be filtered is blocked by the top cover on the pressure relief and air release covering device, avoiding the splashing of the stuffing everywhere, ensuring the operation safety and maintaining the civilized and environmental protection of the on-site construction at the same time.

[0036] 4) The present invention proposes a square hammer wall scrubbing and grooving technology. By processing and manufacturing a square hammer wall scrubber with a mud scraper and a wire brush, both the inner and outer walls of the joint I-beam can be cleaned thoroughly. The structure of the wall scrubber is simple and easy to manufacture, saving construction costs and increasing the wall scrubbing efficiency on the basis of ensuring the construction quality. Description of the Drawings

[0037] Figure 1 It is a schematic diagram of the cross-hole seismic tomography scanning boulder detection technology;

[0038] Figure 2 It is the front view of the drilling construction of the blasting hole;

[0039] Figure 3 It is a schematic diagram of the installation of the arc-shaped steel plate on the drill pipe;

[0040] Figure 4 Schematic diagram of the distribution of blasting holes for boulders with different thicknesses;

[0041] Figure 5 Schematic diagram of the explosive installation for bead-shaped boulders;

[0042] Figure 6 Schematic diagram of the structure of the pressure relief and air release covering device;

[0043] Figure 7 Schematic diagram of the pressure relief and air release covering technology at the top opening of the blasting hole;

[0044] Figure 8 Top view of the square hammer wall scrubber;

[0045] Figure 9 Front view of the square hammer wall scrubber.

[0046] Explanation of the reference numerals in the drawings: 1 - computer, 2 - signal line, 3 - transmitter, 4 - receiver, 5 - ground, 6 - transmitter, 7 - PE pipe, 8 - receiver, 9 - top sealing cover, 10 - boulder, 11 - detection path, 12 - bottom sealing cover, 13 - arc-shaped steel plate, 14 - drill pipe, 15 - drill hole, 16 - drilling tool, 17 - drill bit, 18 - blasting hole, 19 - diaphragm wall, 20 - empty hole, 21 - large boulder, 22 - small boulder, 23 - detonator cord, 24 - PVC pipe, 25 - explosive, 26 - position of the upper boulder, 27 - position of the lower boulder, 28 - steel plate, 29 - steel pipe, 30 - top cover, 31 - connecting piece, 32 - bamboo cover plate, 33 - filling material, 34 - square hammer wall scrubber, 35 - lifting ring, 36 - mud scraper, 37 - arc-shaped steel plate, 38 - wire brush. Specific implementation manners

[0047] The present invention will be further described below in conjunction with embodiments. The description of the following embodiments is only used to help understand the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several modifications can still be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

[0048] Embodiment 1

[0049] As an embodiment, as Figures 1 to 9 shown, this construction method for detecting the diaphragm wall of the boulder formation by cross-hole seismic tomography includes the following construction steps:

[0050] S1. Boulders Detection: Bury the PE pipe 7, and form a detection path 11 in the measurement area through the fan-shaped penetration method of one transmitter and multiple receivers to detect the position of the boulder 10. First, drill holes at designated positions on the site ground 5. After closing the bottom of the PE pipe 7 with the bottom seal cover 12, bury it into the holes. Then, place the transmitter 6 and the receiver 8 into the PE pipes 7 arranged on both sides respectively. Connect the transmitter 6 and the receiver 8 to the transmitter 3 and the receiver 4 on-site using data cables, and finally connect them to the interface of the terminal computer 1 together. Then, start the equipment on-site. Through the working mode of one transmitter and multiple receivers of the transmitter 6 and the receiver 8, form a dense detection path 11 in the measurement area, and accurately detect the position information of the boulder 10 intuitively based on the measurement data obtained by the computer 1. Finally, mark and record the position information of the boulder 10 at the current measurement part for subsequent processing construction.

[0051] S2. Pre-explosion Decomposition and Punching of Beaded Boulder Strata: After the detection work within the construction range of the diaphragm wall 19 is completed, drill blast holes 18 on-site according to the detection results, arrange the blast holes 18 and bury the PVC pipes 24 with sealed bottoms. Place explosives 25 at the corresponding positions of the boulders 10 inside the PVC pipes 24.

[0052] S3. Pressure Relief and Air Release Covering at the Top of Blast Holes: Seal the PVC pipes 24, install the pressure relief and air release covering device, and conduct blasting operations after applying pressure above the pressure relief and air release covering device.

[0053] S4. Square Hammer Wall Brushing and Groove Cleaning: Scrape and clean the sundries on the I-beam at the groove section joint, and pour the diaphragm wall.

[0054] Embodiment 2

[0055] As another embodiment, this Embodiment 2 is proposed based on Embodiment 1. A more specific construction method for a diaphragm wall in a boulder formation by cross-hole seismic tomography detection:

[0056] As Figure 1 shown, first drill holes and bury the PE pipes 7 on the ground 5 near the detection area. The buried PE pipes 7 are 0.5 m higher than the ground 5, and protection work is done well. Then, place the transmitter 6 and the receiver 8 into the PE pipes 7 arranged on both sides, and connect the transmitter 6 and the receiver 8 to the transmitter 3 and the receiver 4 respectively. Finally, connect them to the terminal computer 1 using the signal line 2. Then, start the equipment to control on-site measurement and data transmission through the computer 1. Form a dense detection path 11 in the measurement area through the fan-shaped penetration mode of one transmitter and multiple receivers. Finally, conduct calculation and analysis based on the measurement data to intuitively and accurately detect the position information of the boulder 10, and mark and record it for subsequent processing.

[0057] As Figures 2 to 5As shown in the figure, after on-site detection is completed, the construction of the blasting hole 18 drilling 15 is carried out. First, an arc-shaped steel plate 13 is installed on the drill rod 14 of the drill to ensure that the verticality can be guaranteed during construction. The coring holes are drilled for the boulders within the diaphragm wall 19 groove section by the lower drill tool 16 and the drill bit 17. For the large boulders 21 and small boulders 22 with different widths, the blasting holes 18 are arranged specifically. Then, after the blasting hole 18 is drilled, a PVC pipe 24 is placed, and the bottom of the pipe is sealed with a bottom seal cover 12. Subsequently, the explosive 25 is intermittently installed at the upper boulder position 26 and the lower boulder position 27 according to the distribution of the string-shaped boulders. Finally, after all the on-site work arrangements are completed, the professional personnel detonate the boulders through the detonating fuse 23 to decompose the boulders.

[0058] In step S2, first, an arc-shaped steel plate 13 is installed outside the drill rod 14 of the drill to ensure the verticality of the drilled hole and avoid path deviation when the lower drill tool 16 and the drill bit 17 carry out coring holes for the boulders within the diaphragm wall 19 groove section. Subsequently, the blasting holes 18 are arranged according to the situation of the boulders invading the diaphragm wall. For the large boulders 21 with a width greater than the thickness of the diaphragm wall 19, the blasting holes 18 are arranged in a plum blossom shape with a spacing of 1.0 m in three rows. For the small boulders 22 with a width less than the thickness of the diaphragm wall 19, the blasting holes 18 are arranged in a single row inside and empty holes 20 are arranged on both sides to facilitate the loosening and displacement of the small boulders 22 towards both sides during blasting. Then, after the bottom of the PVC pipe 24 is sealed with a bottom seal cover 12, it is buried in the blasting hole 18, and the explosive 25 is intermittently placed according to the specific upper boulder position 26 and lower boulder position 27, so that the explosive 25 is only placed at the boulder position. Finally, after the detonating fuse 23 is led out above the ground 5, the orifice treatment of the blasting hole 18 is carried out for the next step.

[0059] It should be noted that the same or similar parts in this embodiment and Embodiment 1 can be referred to each other and will not be elaborated in this application.

[0060] Embodiment 3

[0061] As another embodiment, this Embodiment 3 is proposed on the basis of Embodiment 1 and Embodiment 2. A more specific construction method for detecting the diaphragm wall of the boulder formation by cross-hole seismic tomography:

[0062] In step S3, before the blasting construction, a pressure relief and air release covering device is customized at the production factory. It is mainly composed of a steel plate 28, a steel pipe 29, a top cover 30, and a connecting piece 31 fixedly connected. When conducting the construction of the orifice treatment of the blasting hole 18, first, the upper cavity of the PVC pipe 24 is blocked with a stuffing 33. When using the stuffing 33 to block the upper cavity of the PVC pipe 24, the blocking height is controlled at 4 - 5 m. Subsequently, a woven bamboo cover plate 32 is installed at the orifice ground 5, so that while the orifice maintains pressure relief and air permeability, it can filter most of the orifice stuffing 33 ejected by the blasting. The stuffing that fails to be filtered is blocked by the top cover 30 on the pressure relief and air release covering device. Then, the customized pressure relief and air release covering device is installed above the bamboo cover plate 32, and multiple sandbags 31 are carried and pressed on the bottom steel plate 28 of the pressure relief and air release covering device. Finally, professional personnel on-site conduct the blasting operation through the detonator guide tube 23. After the blasting is completed, the site is cleaned and subsequent operations are carried out. There is a gap between the top cover 30 of the pressure relief and air release covering device and the steel pipe 29, which facilitates the leading-out of the detonator guide tube 23 while allowing pressure relief and air release and blocking the splashing of blasting objects.

[0063] As Figure 6 and Figure 7 shown, before the blasting construction, first, the upper cavity of the PVC pipe 24 is blocked with a stuffing 33. Then, a woven bamboo cover plate 32 is installed at the orifice ground 5 of the PVC pipe 24, and the detonator guide tube 23 is led out of the orifice at the upper part. Subsequently, a pressure relief and air release covering device is installed above the bamboo cover plate 32, and sandbags 31 are carried and pressed on the steel plate 28 of the pressure relief and air release covering device. During the blasting, the bamboo cover plate 32 cooperates with the pressure relief and air release covering device and the sandbags 31 to prevent the stuffing 33 from splashing during the blasting. Finally, the blasting operation is carried out through the detonator guide tube 23, and the site is cleaned after the blasting is completed.

[0064] In step S4, during the construction of slot joint cleaning and brushing, first, a square hammer wall brushing device 34 with a mud scraping plate 36 and a wire brush 38 is processed and manufactured. Subsequently, the on-site hoisting equipment uses the lifting ring 35 at the top of the square hammer wall brushing device 34 to lift and place it into the slot section. Then, the end mud scraping plate 36 is used to brush the slot joint up and down to scrape off the sundries on the joint I-beam. Finally, the inner wall sundries of the I-beam joint are carefully cleaned with the end with the wire brush 38. After cleaning, the construction of the diaphragm wall is carried out.

[0065] As Figure 8 and Figure 9 shown, during the construction of slot joint cleaning and brushing, the square hammer wall brushing device 34 is used to clean the joint part up and down. First, the square hammer wall brushing device 34 is processed and manufactured and transported to the construction location. Then, the on-site hoisting equipment uses the lifting ring 35 to lift the square hammer wall brushing device 34. Subsequently, the end mud scraping plate 36 is used to brush the I-beam joint up and down to remove the joint sundries. Finally, the inner wall of the I-beam joint is carefully cleaned with the end with the wire brush 38.

[0066] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. For the same or similar parts among the various embodiments, reference can be made to each other.

Claims

1. A construction method for detecting diaphragm walls in boulder formations by cross-hole seismic tomography, characterized in that, It includes the following construction steps: S1. Boulders detection: Bury PE pipes, and form a detection path in the measurement area through the fan-shaped penetration method of one transmitter and multiple receivers to detect the positions of boulders; S2. Pre-explosion decomposition and punching of beaded boulder stratum: Arrange blast holes and bury PVC pipes with sealed bottoms, and place explosives at the positions corresponding to the boulders inside the PVC pipes; S3. Pressure relief and gas release covering at the top of blast holes: Seal the PVC pipes, install a pressure relief and gas release covering device, and conduct blasting operations after applying pressure above the pressure relief and gas release covering device; S4. Square hammer wall brushing and trench cleaning: Scrape and clean the sundries on the I-beam at the groove section joint, and pour the diaphragm wall; Step S1 includes: S1.

1. Drill holes on the ground at the construction position and bury PE pipes; S1.

2. Place the transmitter and receiver into the PE pipes arranged on both sides of the boulder respectively to form a detection path in the measurement area; S1.

3. Connect the transmitter and receiver to the transmitter and receiver instrument respectively, and connect them to the terminal computer through signal lines to obtain measurement data; S1.

4. Analyze the measurement data to detect the position where the boulder is located; The PE pipe is higher than the ground; the bottom of the PE pipe is completely sealed with a bottom seal cover, and a top seal cover is provided at the top of the PE pipe, and a signal line installation position is reserved on the top seal cover; Step S3 includes: S3.

1. Lead the detonator into the orifice of the blast hole at the upper part of the PVC pipe, and use stuffing to block the upper cavity of the PVC pipe; S3.

2. Set up a bamboo cover plate at the ground of the orifice, and install a pressure relief and gas release covering device above the bamboo cover plate; Apply pressure to the steel plate of the pressure relief and gas release covering device by transporting sandbags; The pressure relief and gas release covering device includes a steel plate, a steel pipe, a top cover and a connecting piece. A hole is opened in the center of the steel plate to connect the steel pipe, the top of the steel pipe is connected to the top cover through the connecting piece, and the sandbag is installed on the steel plate.

2. The construction method of the diaphragm wall of the boulder formation by cross-hole seismic tomography detection according to claim 1, characterized in that, Step S2 includes: S2.

1. Drill holes for boulder construction as blast holes; S2.

2. Place a PVC pipe with a sealed bottom at the bottom in the blast hole; S2.

3. Install explosives in the PVC pipe according to the detected positions of the boulders.

3. The construction method of the diaphragm wall of the underground continuous wall in the boulder stratum by cross-hole seismic tomography according to claim 2, characterized in that, For large boulders with a width greater than the thickness of the diaphragm wall, blast holes are arranged in a plum blossom shape; for small boulders with a width less than the thickness of the diaphragm wall, blast holes are arranged in a single row inside and empty holes are arranged on both sides of the small boulder.

4. The construction method of the diaphragm wall of the boulder stratum by cross-hole seismic tomography according to claim 1, characterized in that, The blocking height of the stuffing blocking the upper cavity of the PVC pipe is controlled at 4 - 5m.

5. The construction method of the diaphragm wall in the boulder stratum by cross-hole seismic tomography according to claim 1, characterized in that Step S4 includes: S4.

1. Use a lifting device to lift the square hammer wall brushing device with the help of a lifting ring; One end of the square hammer wall brushing device is provided with an end mud scraping plate, and the other end is provided with a wire brush; S4.

2. Use the end mud scraping plate to brush the I-beam joint up and down; S4.

3. Use the end with the wire brush to clean the inner wall of the I-beam joint.

6. The seismic wave crosshole tomography for detecting the diaphragm wall of the boulder stratum, which is characterized in that it is obtained by the method according to any one of claims 1 to 5.

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