A method and device for taking cores by multiple sets of pipes in a multi-pipeline karst broken stratum site
By adding a wire mesh or blocking structure between the drill pipe and the core casing, and combining this with water or mud support inside the drill pipe, the problem of incomplete core sampling in karst fractured strata was solved, enabling complete core sampling and geological exploration under multi-layered geological conditions.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHINA CONSTR FIRST GROUP THE FIFTH CONSTR
- Filing Date
- 2023-05-05
- Publication Date
- 2026-06-09
AI Technical Summary
In fractured strata of karst regions, traditional coring methods are difficult to effectively extract small fragments of rock, resulting in incomplete coring.
The multi-casing coring method is adopted, which involves adding metal wires between different drill pipes and coring casings to form a net or blocking structure to assist the drill bit in drilling. Water or mud is also passed through the drill pipes for support, ensuring the complete sampling of broken rocks and rock strata.
It enables complete core sampling under different geological conditions, improving the accuracy and efficiency of geological exploration, especially in tunnel development under urban roads with multiple pipelines and karst caves, ensuring the smooth progress of the core sampling process.
Smart Images
Figure CN116556865B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of geological supplementary exploration and coring, and in particular to a method and apparatus for multi-casing coring in karst fractured strata in multi-pipeline sites. Background Technology
[0002] Constructing bridges or tunnels in karst areas presents numerous challenges due to the complexity of karst development, making the provision of accurate and reliable geological data a highly complex system engineering task. To understand the geological conditions of the strata, rock sampling is necessary, and core sampling is performed using a core barrel. Traditionally, the core barrel is attached to the bottom of the drill pipe near the drill bit. After the core cutting head cuts into the formation, the core barrel can be used to continuously extract cores, which are then removed from the drill pipe. In most areas, cable-operated core barrels are used because the core extraction process does not require retrieving the drill pipe from the well to extract rock cores and then continuing extraction; instead, the core barrel is simply inserted into the drill pipe, automatically locked in the core extraction position, reaches the bottom of the well, and allows for continuous core extraction.
[0003] In areas with highly developed limestone karst caves, where the detailed exploration revealed a cave rate of 82.6%, additional drilling was conducted within the road area to ensure the smooth passage of the tunnel beneath the road. Furthermore, due to the dense network of pipelines beneath the municipal road, including water supply, gas, electricity, telecommunications, rainwater, and sewage pipes, the additional drilling had to penetrate sand layers, fractured and strongly weathered granular rock layers, and enter the limestone caves. When encountering upper soft, permeable strata and lower fractured karst strata, conventional geological drilling for core sampling was used, employing a 130mm diameter diamond drill bit and a 127mm diameter connecting casing to protect the permeable strata. The casing was then inserted into the rock layer, and a 91mm diameter coring diamond drill bit was used for core sampling.
[0004] Regarding the aforementioned technologies, the inventors believe that when core sampling is performed on fractured rock layers in karst caves, there is a drawback: small fragments of rock cannot be brought to the surface. Summary of the Invention
[0005] In order to achieve complete coring in different geological formations, this application provides a method and apparatus for multi-casing coring in karst fractured formations in multi-pipeline sites.
[0006] This application provides a method and apparatus for multi-casing coring in karst fractured strata at multi-pipeline sites, employing the following technical solution:
[0007] A method for multi-casing coring in karst fractured strata at multi-pipeline sites includes the following steps:
[0008] Determine the location of the drilling points and fix the core drilling device;
[0009] A first core sleeve and a first drill bit are installed on the core drilling device to drill cores in the concrete and soil layers located on the municipal road.
[0010] Install a second core sleeve and a second drill rod with a second drill bit on the core drilling device. Insert a first metal wire into the second drill rod to the bottom of the second drill bit or clamp it on the side of the second drill bit. Drill holes in the broken rock layer located below the soil layer until water gushes out and then core the rock.
[0011] A third drill rod with a third drill bit is installed on the core drilling device. A second metal wire is inserted into the third drill rod to the bottom of the third drill bit or is stuck on the side of the third drill bit. A hole is drilled in the fully weathered rock layer located below the fractured rock layer, and the operation is completed after core sampling.
[0012] By adopting the above technical solution, in areas with multiple pipelines and well-developed karst caves under urban roads, if tunnel development is required, prior geological surveys are necessary. The geology typically consists of three layers. The first layer is a concrete layer, where the first drill bit is used to drill into the ground, followed by core sampling using the first core casing. During the core sampling process, because the concrete and the soil at a certain depth below it are relatively dense, core sampling can be completed smoothly without auxiliary equipment. The second layer is a fractured rock layer. Because many broken rocks are present during drilling in this layer, the second drill bit is used to ensure... The broken stones are smoothly removed from the borehole. A first wire is added between the second drill rod and the second core casing. The first wire follows the drilling range of the second drill bit and is engaged at the bottom or side of the second drill bit, forming a net under the second core casing to facilitate the core extraction of the broken stones. The third layer is a fully weathered rock layer. When drilling into the fully weathered rock layer, a second wire is added inside the third drill rod, forming a net at the end of the third drill rod. This facilitates the sampling of the broken stones formed after drilling into the fully weathered rock layer. This allows for complete core extraction in different geological conditions, which is beneficial for geological exploration.
[0013] Preferably, there is a gap between the second drill rod and the second core sleeve, water flows through the inside of the second drill rod, and the first metal wire is arranged between the second drill rod and the second core sleeve. There are 4-5 first metal wires, and multiple first metal wires are stuck between the second core sleeve and the second drill rod, or stuck at the bottom of the second drill bit, or stuck on the side of the second drill bit.
[0014] By adopting the above technical solution, the water flow inside the second drill rod facilitates drilling and cools the second drill bit and drill rod. The first metal wire fills the gap between the second drill rod and the second core casing. There are 4-5 first metal wires. In addition to filling the gap between the second drill rod and the second core casing, the multiple first metal wires present various states during the drilling process of the second drill bit. When the multiple first metal wires are partially stuck at the second drill bit, partially stuck at the side of the second drill bit, and bent and coiled at the bottom of the second core casing, they form a net or obstruction, allowing the second core casing to retrieve the core smoothly. When the multiple first metal wires are always located between the second drill rod and the second core casing, the multiple first metal wires can increase the friction between the broken rocks, making it easier for the second core casing to retrieve the core.
[0015] Preferably, the third drill rod is filled with mud, the second metal wire is selected with a diameter of 20mm and a length of 230mm, and there are 3-4 second metal wires. Multiple second metal wires are locked inside the third drill rod, or locked at the bottom of the third drill bit, or locked on the side of the third drill bit.
[0016] By adopting the above technical solution, during the drilling process, the mud inside the third drill rod flows out through the drill bit and remains on the inner wall of the borehole, thus forming preliminary support in the fully weathered Yancheng and preventing collapse. Three to four second iron wires with a diameter of 20mm and a length of 230mm are added inside the third drill rod. These multiple second metal wires exhibit various states during the drilling process. When some of the second metal wires are partially stuck at the third drill bit, and some are stuck on the side of the third drill bit, and the whole wire is bent and coiled at the bottom of the third drill rod, it forms a net or obstruction, allowing the third drill rod to successfully extract the core. When the multiple second metal wires remain inside the third drill rod, they increase the friction between the broken stones, facilitating core extraction.
[0017] Preferably, the diameter of the first core sleeve is greater than or equal to that of the second core sleeve; the diameters of the first drill rod, the second drill rod, and the third drill rod are the same; or the diameter of the first drill rod is greater than that of the second drill rod, and the diameter of the second drill rod is greater than that of the third drill rod; the dimensions of the first drill bit, the second drill bit, and the third drill bit correspond to the dimensions of the first drill rod, the second drill rod, and the third drill rod, respectively.
[0018] By adopting the above technical solution, the dimensions of the first core casing, the second core casing, and the third drill rod can be the same. When the dimensions are the same, in order to facilitate core drilling operations, the number and size of the first metal wire and the second metal wire are the same during use. In order to facilitate the smooth removal of the core casing and drill rod from the hole after core extraction and drilling, the optimal solution is that the size of the first drill rod is larger than that of the second drill rod, the size of the first core casing is larger than that of the second core casing, and the size of the second drill rod is larger than that of the third drill rod. This achieves the effect of multi-layer core drilling, which can achieve complete core drilling even when facing different formations, and the core drilling process is more convenient.
[0019] Preferably, the diameter of the second drill rod is 110mm, the size of the second core casing is 108mm, the second core casing is located 0.6m above the ground, and a first protective casing is fitted on the side of the second drill rod away from the second core casing, the diameter of the first protective casing being 127mm.
[0020] By adopting the above technical solution, water is circulated between the second drill rod and the second core sleeve to facilitate core extraction and processing. This also facilitates core extraction during the drilling process. A second drill rod with a diameter of 110mm is selected, and a second core sleeve with a diameter smaller than that of the second drill rod is selected, making it easier to remove the second core sleeve from the hole during the core extraction process.
[0021] Preferably, the diameter of the second drill rod is larger than the diameter of the third drill rod, the diameter of the third drill rod is selected to be 91mm, and the third drill bit is a diamond drill bit.
[0022] By adopting the above technical solution, the size of the second drill rod is smaller than that of the first drill rod and larger than that of the third drill rod, making it easier for the diamond drill bit to perform drilling operations.
[0023] Preferably, the first drill bit is a diamond drill bit with a diameter of 130 mm, the first core casing has a diameter of 127 mm, and the first core casing extends to 6 m below the ground surface.
[0024] By adopting the above technical solution, the first drill bit and the first core casing are mainly used for concrete layers and soil layers. Large-sized drill bits and core casings are required, with a maximum depth of up to 6m underground.
[0025] Preferably, the steps for determining the location of the layout hole are as follows:
[0026] Lay out the pipeline on-site according to the electronic pipeline drawings;
[0027] Clearly label the pipeline routes;
[0028] Please have the pipeline owner confirm the pipeline route on-site.
[0029] Pipeline detection personnel used handheld detection instruments to reconfirm the route of pipelines beneath the road.
[0030] Select locations without pipelines to determine the locations of the layout holes.
[0031] By adopting the above technical solution, it is necessary to detect the location and pipeline direction of various pipelines under the city, and then select a location without pipelines to drill and extract core samples.
[0032] Preferably, after determining the location of the layout hole, the concrete is initially drilled and cored using the first drill bit and the first core casing. After the initial drilling and cored sampling, a second survey of the ground is conducted using a heavy-duty cone penetration test.
[0033] By adopting the above technical solution, if a plastic tube is found, it will bounce back; if a metal tube is found, the sound will be different. After the test, the drilling and core extraction operation will continue in the area where there is no tube.
[0034] A multi-casing coring device for karst fractured strata in multi-pipeline sites includes:
[0035] The hoisting system is used for hoisting and lowering drill tools, running casing, and controlling drill bits and drill tools. It includes the derrick, winch, traveling system, wire rope, overhead crane, traveling block, and hook.
[0036] Rotary systems are used to drive drill tools, drill bits, etc. to rotate and break rocks, load and unload drill tool threads, and perform special operations. These include rotary tables, square drill pipes, drill string swivels, top drive systems, and downhole power drilling tools.
[0037] The circulation system is used to circulate the mud, including a liquid vibrating screen, a desander, and a desliming device.
[0038] The power system, used to drive the operation of winches, rotary tables, drilling pumps and other working machines, includes electric motors and diesel engines;
[0039] The transmission system, used to transmit and distribute the engine's energy to the various working machines, includes a reducer, clutch, shaft, and chain;
[0040] A control system is used to manipulate various systems to work in a coordinated manner, including computers, sensors, signal transmission media, and control actuators;
[0041] Base, used to facilitate the installation and fixation of various equipment for drilling rigs, including drill platform base and pump base;
[0042] Auxiliary equipment, used to assist in operations.
[0043] By adopting the above technical solution, the sampling operation is completed using a vertical drilling machine.
[0044] In summary, this application includes at least one of the following beneficial technical effects:
[0045] 1. In areas with numerous underground pipelines and well-developed karst caves, if tunnel development is required, prior geological surveys are necessary. The geology typically consists of three layers. The first layer is a concrete layer. In this layer, the first drill bit is used to drill into the ground, followed by core sampling using the first core casing. During the core sampling process, because the concrete and the soil at a certain depth below it are relatively dense, auxiliary equipment is not required to complete the core sampling smoothly. The second layer is a fractured rock layer. Since many broken rocks will be present during drilling in this layer, the second drill bit is used to ensure that the broken rocks are extracted. The block was successfully removed from the borehole. A first wire was added between the second drill rod and the second core casing. The first wire was engaged with the bottom or side of the second drill bit as the second drill bit drilled, forming a net under the second core casing to facilitate the core extraction of the broken rock. The third layer is a fully weathered rock layer. When drilling into the fully weathered rock layer, a second wire was added inside the third drill rod, forming a net at the end of the third drill rod. This facilitated the sampling of the broken stones formed after drilling into the fully weathered rock layer. This allowed for complete core extraction in different geological conditions, which is beneficial for geological exploration.
[0046] 2. The water circulation inside the second drill rod facilitates drilling and cools the second drill bit and drill rod. The first metal wire fills the gap between the second drill rod and the second core casing. There are 4-5 first metal wires. In addition to filling the gap between the second drill rod and the second core casing, the multiple first metal wires present various states during the drilling process of the second drill bit. When the multiple first metal wires are partially stuck at the second drill bit, partially stuck on the side of the second drill bit, and bent and coiled at the bottom of the second core casing, they form a net or obstruction, allowing the second core casing to retrieve the core smoothly. When the multiple first metal wires are always between the second drill rod and the second core casing, the multiple first metal wires can increase the friction between the broken rocks, making it easier for the second core casing to retrieve the core.
[0047] 3. The dimensions of the first core casing, the second core casing, and the third drill rod can be the same. When the dimensions are the same, in order to facilitate core drilling operations, the number and size of the first and second metal wires are the same. In order to facilitate the smooth removal of the core casing and drill rod from the hole after core extraction and drilling, the optimal solution is that the size of the first drill rod is larger than that of the second drill rod, the size of the first core casing is larger than that of the second core casing, and the size of the second drill rod is larger than that of the third drill rod. This achieves the effect of multi-layer core drilling, which can achieve complete core drilling in different formations and makes the core drilling process more convenient. Attached Figure Description
[0048] Figure 1This is a schematic diagram illustrating the completion steps of a multi-casing coring method in karst fractured strata at a multi-pipeline site, as described in an embodiment of this application.
[0049] Figure 2 This is a schematic diagram illustrating the construction process of this application;
[0050] Figure 3 This is a schematic diagram illustrating the drilling of holes in the concrete and soil layers;
[0051] Figure 4 This is a structural diagram illustrating the use of metal wire. Detailed Implementation
[0052] The following is in conjunction with the appendix Figure 1-4 This application will be described in further detail.
[0053] This application discloses a method and apparatus for multi-casing coring in karst fractured strata at multi-pipeline sites. (Refer to...) Figure 1 A method for multi-casing coring in karst fractured strata at multi-pipeline sites, comprising the following steps:
[0054] Reference Figure 1 and Figure 2 S1, Determine the location of the drilling points and fix the drilling and core sampling device;
[0055] When determining the location of the borehole, the pipeline must first be laid out on-site according to the electronic pipeline drawings. The pipeline owner must confirm the pipeline route on-site. Before the geological drilling construction, the pipeline detection personnel must use a handheld detection instrument to confirm the pipeline route under the road again, select a location without pipelines to determine the location of the borehole, fix the core drilling device at the location to be constructed, and then carry out the geological drilling construction.
[0056] Reference Figure 1 and Figure 2 S2, Install the first core sleeve and the first drill bit on the core drilling device to drill cores in the concrete and soil layers located on the municipal road.
[0057] The first drill bit is a diamond drill bit. Optionally, the diameter of the first drill bit is large, and the diameter of the first core casing is slightly smaller than the diameter of the first drill bit. The first core casing extends to below the ground surface. The first drill bit and the first core casing are mainly used for concrete and soil layers, so large-sized drill bits and core casings are required. During the entire core sampling process, because the concrete and the soil at a certain depth below the concrete are relatively dense, core sampling can be completed smoothly without auxiliary devices.
[0058] The concrete is initially drilled and cored using the first drill bit and the first coring casing. After the initial drilling and coring, a second survey of the ground is conducted using a heavy-duty cone penetrometer. If a plastic tube is found, it will bounce back; if a metal tube is found, the sound will be different. After the test, drilling and coring operations will continue in areas without pipes.
[0059] Reference Figure 2 and Figure 3 S3, Install a second core sleeve and a second drill rod with a second drill bit on the core drilling device, insert a first metal wire into the second drill rod to the bottom of the second drill bit or wedge it on the side of the second drill bit, drill a hole in the broken rock layer located below the soil layer until water gushing out and then core the rock.
[0060] There is a gap between the second drill rod and the second core casing. Water flows through the inside of the second drill rod. The first metal wire is set between the second drill rod and the second core casing. There are 4-5 first metal wires. Multiple first metal wires are stuck between the second core casing and the second drill rod, or stuck at the bottom of the second drill bit, or stuck on the side of the second drill bit.
[0061] Water circulation inside the second drill rod facilitates drilling and cools the second drill bit and drill rod. Four to five first metal wires fill the gap between the second drill rod and the second core casing. Besides filling the gap, these wires exhibit various states during the drilling process. When some wires are partially engaged with the second drill bit, others with its side, and the entire wire is bent and coiled at the bottom of the second core casing, they form a net or obstruction, allowing for smooth core extraction. When multiple first metal wires remain between the second drill rod and the second core casing, they increase friction between the broken rocks, facilitating core extraction.
[0062] Optionally, the first core sleeve and the second core sleeve are the same size, and the first drill rod is the same size as the second drill rod. In this case, if drilling and core extraction are performed, the second core sleeve is not easy to remove from the hole. Alternatively, the first core sleeve is larger than the second core sleeve, and the first drill rod is larger than the second drill rod. In this case, it is easier to use the second core sleeve for core extraction.
[0063] Optionally, the first drill bit is a diamond drill bit, the diameter of the first drill bit and the first drill rod is 130mm, the diameter of the first core casing is 127mm, and the first core casing extends to 6m below the ground; the diameter of the second drill rod is selected as 110mm, the size of the second core casing is 108mm, and the second core casing is located 0.6m above the ground.
[0064] Reference Figure 3 and Figure 4S3, Install a third drill rod with a third drill bit on the core drilling device, insert a second metal wire into the third drill rod to the bottom of the third drill bit or clamp it on the side of the third drill bit, drill a hole in the fully weathered rock layer located below the fractured rock layer, and complete the operation after core sampling;
[0065] The third drill pipe is filled with mud. The second metal wire has a diameter of 20mm and a length of 230mm. There are 3-4 second metal wires. Multiple second metal wires are installed inside the third drill pipe, or at the bottom of the third drill bit, or at the side of the third drill bit.
[0066] During drilling, the mud inside the third drill rod flows out through the drill bit and remains on the inner wall of the borehole, thus forming initial support in the strongly weathered Yancheng and preventing collapse. Three to four second iron wires, each 20mm in diameter and 230mm in length, are added inside the third drill rod. These second metal wires exhibit various states during the drilling process. When some of the second metal wires are partially engaged with the third drill bit, or partially engaged with the side of the third drill bit, and when they are bent and coiled at the bottom of the third drill rod, they form a net or obstruction, allowing for smooth core extraction. When the second metal wires remain inside the third drill rod, they increase the friction between the broken stones, facilitating core extraction.
[0067] Optionally, the third drill rod has the same dimensions as the second drill rod. In this case, when coring the fully weathered rock layer, the size of the third drill rod is larger, so the number of second metal wires needs to be increased, and it is not easy to pull out during the coring process. Optionally, the diameter of the third drill rod is smaller than that of the second drill rod. The diameter of the third drill rod is selected as 91mm, and the third drill bit is a diamond drill bit.
[0068] Reference Figure 2 Preferably, in steps S1-S3, the hole wall needs to be reinforced after each drilling. A 130mm diameter diamond drill bit is used, water is passed through the drill rod, and the drill penetrates the concrete layer of the municipal road. Then, a heavy-duty cone penetration test is used, and a 127mm diameter steel casing is used to hammer and extract cores to a depth of 6m below the ground. After confirming that there are no pipelines in the borehole, the 127mm diameter steel casing is used as a protective casing for the fill and sand layers. The drill rod is replaced with a 91mm diameter diamond core drill bit, and mud is used for wall protection during drilling. In a fully weathered and fractured rock stratum, the rock core is in the form of small fragments. The water system is connected, and water gushed into the borehole. The fractured rock mass collapses when it encounters water, filling the borehole. A 110mm diameter drill bit is used to drill to the fractured stratum. The drill bit is connected to a 108mm diameter steel casing for wall protection. The 108mm diameter steel casing is extended to 0.6m above the ground. Another 108mm diameter steel casing is then inserted inside a 127mm diameter steel casing, forming a method of multiple casings for wall protection in different strata.
[0069] When the drill bit enters the fractured rock strata and karst caves, the top of the rock strata is thin and broken, and the rock to be cored is in the form of small fragments. Before the drilling of this section of the core drill rod is completed, multiple iron wires are manually inserted into the hollow drill rod from the top. Water is passed through the drill rod from top to bottom, and the iron wires slide down the top of the hollow drill rod to the bottom of the rotating drill bit, where they are stuck on the side or bottom of the drill bit to prevent the broken rock fragments from falling. The drilling rig then lifts the drill rod and the core bucket to the ground to achieve the purpose of core extraction of small rock fragments.
[0070] Embodiments of the present invention also include an apparatus for performing the above-described method, comprising: a lifting system,
[0071] The system comprises a rotary system, a circulation system, a power system, a transmission system, a control system, a base, and auxiliary equipment. The hoisting system is used for raising and lowering drill strings, running casing, and controlling drill bits and drill tools, including the derrick, winch, traveling block, wire rope, overhead crane, traveling block, and hook. The rotary system is used to drive the drill strings and drill bits to rotate and break rocks, load and unload drill string threads, and perform special operations, including the rotary table, angular drill pipe, drill string swivel, top drive system, and downhole power drill tools. The circulation system is used to circulate drilling mud, including a hydraulic vibratory screen, desander, and desilter. The power system drives the winch, rotary table, drilling pump, and other working machines, including electric motors and diesel engines. The transmission system transmits and distributes the engine's energy to each working machine, including reducers, clutches, shafts, and chains. The control system coordinates the operation of all systems, including computers, sensors, signal transmission media, and control actuators. The base facilitates the installation and fixation of various equipment on the drilling rig, including the drill platform base and pump base. Auxiliary equipment is used to assist in operations.
[0072] The implementation principle of this application embodiment is as follows: In areas with multiple pipelines and well-developed karst caves under urban roads, if tunnel development is required, geological surveys must be conducted in advance. The geology is typically divided into three layers. The first layer is a concrete layer. At this stage, a first drill bit is used to drill into the ground, and then a first core casing is used for core sampling. During the core sampling process, because the concrete and the soil at a certain depth below it are relatively dense, core sampling can be completed smoothly without auxiliary equipment. The second layer is a fractured rock layer. Because many broken rocks are present during drilling in this layer, a second drill bit is used to drill through it. To ensure… The system allows for the smooth extraction of broken rocks from the borehole. A first wire is inserted between the second drill rod and the second core casing. The first wire follows the drilling motion of the second drill bit and is engaged at the bottom or side of the second drill bit, forming a net under the second core casing. This facilitates the core extraction of broken rocks. The third layer is a fully weathered rock layer. When drilling through this layer, a second wire is added inside the third drill rod, forming a net at the end of the third drill rod. This allows for the sampling of broken stones formed after drilling through the fully weathered rock layer. This ensures complete core extraction even in different geological formations, facilitating geological exploration.
[0073] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.
Claims
1. A method for multi-casing coring in karst fractured strata at multi-pipeline sites, characterized in that, Includes the following steps: Determine the location of the layout holes and fix the drilling and core sampling device; A first core sleeve, a first drill rod, and a first drill bit are installed on the core drilling device to drill cores in the concrete and soil layers located on the municipal road. Install a second core sleeve and a second drill rod with a second drill bit on the core drilling device. Insert a first metal wire into the second drill rod to the bottom of the second drill bit or clamp it on the side of the second drill bit. Drill holes in the broken rock layer located below the soil layer until water gushes out and then core the rock. A third drill rod with a third drill bit is installed on the core drilling device. A second metal wire is inserted into the third drill rod to the bottom of the third drill bit or is secured to the side of the third drill bit. A hole is drilled in the fully weathered rock layer located below the fractured rock layer, and the operation is completed after core sampling. A gap is left between the second drill rod and the second core sleeve. Water flows through the inside of the second drill rod. The first metal wire is set between the second drill rod and the second core sleeve. There are 4-5 first metal wires. Multiple first metal wires are stuck between the second core sleeve and the second drill rod, or stuck at the bottom of the second drill bit, or stuck on the side of the second drill bit. The third drill pipe is filled with mud. The second metal wire has a diameter of 20mm and a length of 230mm. There are 3-4 second metal wires. Multiple second metal wires are installed inside the third drill pipe, or at the bottom of the third drill bit, or on the side of the third drill bit. The steps for determining the location of the layout holes are as follows: Lay out the pipeline on-site according to the electronic pipeline drawings; Clearly label the pipeline routes; Please have the pipeline owner confirm the pipeline route on-site. Pipeline detection personnel used handheld detection instruments to reconfirm the route of pipelines beneath the road. Select locations without pipelines to determine the locations of the layout holes.
2. The method for multi-casing coring in karst fractured strata at multi-pipeline sites according to claim 1, characterized in that: The diameter of the first core sleeve is greater than or equal to that of the second core sleeve; the diameters of the first drill rod, the second drill rod, and the third drill rod are the same; or the diameter of the first drill rod is greater than that of the second drill rod, and the diameter of the second drill rod is greater than that of the third drill rod; the dimensions of the first drill bit, the second drill bit, and the third drill bit correspond to the dimensions of the first drill rod, the second drill rod, and the third drill rod, respectively.
3. The method for multi-casing coring in karst fractured strata in multi-pipeline sites according to claim 2, characterized in that: The diameter of the second drill pipe is 110mm, the size of the second core casing is 108mm, the second core casing is located 0.6m above the ground, and a first protective casing is fitted on the side of the second drill pipe away from the second core casing. The diameter of the first protective casing is 127mm.
4. The method for multi-casing coring in karst fractured strata in multi-pipeline sites according to claim 3, characterized in that: The diameter of the second drill rod is larger than that of the third drill rod, the diameter of the third drill rod is selected to be 91mm, and the third drill bit is a diamond drill bit.
5. The method for multi-casing coring in karst fractured strata at multi-pipeline sites according to claim 4, characterized in that: The first drill bit is a diamond drill bit with a diameter of 130 mm. The first core casing has a diameter of 127 mm and extends to 6 m below the ground surface.
6. The method for multi-casing coring in karst fractured strata at multi-pipeline sites according to claim 1, characterized in that: After determining the location of the layout holes, the concrete is initially drilled and cored using the first drill bit and the first core casing. After the initial core drilling, the ground is then surveyed a second time using a heavy-duty cone penetration test.
7. A multi-casing coring apparatus for multi-pipeline sites in karst fractured strata for implementing the multi-casing coring method in any one of claims 1-6, characterized in that, include: The hoisting system is used for hoisting and lowering drill tools, running casing, and controlling drill bits and drill tools. It includes the derrick, winch, traveling system, wire rope, overhead crane, traveling block, and hook. The rotary system, used to drive the drill string to rotate and break rocks, and to load and unload drill string threads, includes a rotary table, angular drill pipe, drill string swivel, top drive system, and downhole power drill string; A circulation system for circulating mud, including a desander and a desilter; The power system, used to drive the winch, rotary table, and drilling pump, includes electric motors and diesel engines; The transmission system, used to transmit and distribute the engine's energy to the various working machines, includes a reducer, clutch, shaft, and chain; A control system is used to manipulate various systems to work in a coordinated manner, including computers, sensors, signal transmission media, and control actuators; Base, used to facilitate the installation and fixation of various equipment for drilling rigs, including drill platform base and pump base; Auxiliary equipment, used to assist in operations.