Vertical drilling array strong earthquake observation device and installation method thereof

Abstract

The invention relates to a vertical drilling array strong earthquake observation device and an installation method of the vertical drilling array strong earthquake observation device. Comprising an earthquake acquisition station arranged on the earth surface, multiple stages of digital three-component earthquake acceleration probes vertically downwards arranged from a well mouth to a well bottom, inter-stage connecting cylinder assemblies connected between the adjacent digital three-component earthquake acceleration probes, and grouting assemblies arranged in a well along the depth of the well; the adjacent digital three-component seismic acceleration probe and interstage connecting cylinder assembly are connected through a joint assembly; all stages of digital three-component seismic acceleration probes are electrically connected together, and the seismic acquisition station is electrically connected with the first stage of digital three-component seismic acceleration probe. According to the vertical drilling array strong earthquake observation device and the installation method thereof, the installation and filling process is simplified, tube wave interference and azimuth angle deviation are eliminated, and whole-course fine monitoring of seismic oscillation spreading from the deep position of the soil layer to the ground surface is achieved.

Description

Technical Field

[0001] The present application belongs to the technical field of strong earthquake monitoring, and specifically relates to a vertical drilling array strong earthquake observation device and an installation method thereof. Background Art

[0002] Site effect is one of the important research topics in engineering seismology, geotechnical seismic engineering and seismology. It has important theoretical significance and engineering application value for near-fault ground motion simulation, ground motion prediction equation establishment, earthquake damage assessment in earthquake-stricken areas, earthquake subdivision, building site selection and seismic fortification, etc. In particular, the western region of my country is rich in water resources, but the fault movement is active, the earthquake intensity is large, and the riverbed cover is thick (tens to hundreds of meters). Carrying out strong ground motion on-site observation to obtain the ground motion response of the dam foundation site with a thick cover in real time, accurately and comprehensively under the action of strong earthquakes is of great significance for the seismic design and seismic damage assessment of hydropower dams with thick cover.

[0003] In the past two decades, many countries and regions around the world have built a large number of vertical drilling seismic arrays (referred to as downhole arrays). These downhole arrays are closely connected to the strata by installing three-dimensional force balance accelerometers at different borehole depths in the same observation site, aiming to capture rich strong ground motion observation data within tens to hundreds of meters near the surface. With the help of the field observation data of the downhole array, the temporal and spatial distribution of ground motion in the soil can be intuitively grasped, the amplification effect of the site on ground motion can be quantitatively evaluated, and the dynamic characteristic parameters of the soil can be identified. Therefore, downhole arrays are recognized as one of the most direct and effective methods for studying the site effects of ground motion.

[0004] At present, the main technical difficulties faced by underground arrays are that the three-dimensional force balance accelerometer is large in size, heavy in weight, high in price, and complex in installation and maintenance, resulting in sparse arrangement density of accelerometers in the array, scarce observation data, and insufficient observation capabilities. Taking the KIK-NET underground array as an example, each array is often equipped with only one three-dimensional force balance accelerometer. As the underground array with the largest number of accelerometers, the WLA array in the United States is also equipped with only 9 three-dimensional force balance accelerometers. Moreover, these 9 accelerometers are installed in different wells, further pushing up the construction and operation and maintenance costs. Faced with the demand for refined seismic observations at sites with 100 meters or deeper formations, the number of accelerometers is obviously too sparse, especially when the soil profile shows significant variability. This lack of accelerometers has an extremely adverse impact on the site effect assessment.

[0005] Compared with traditional accelerometers, MEMS accelerometers have the advantages of small size, light weight, low power consumption and electromagnetic interference, good temperature stability, etc., and due to the development of micromachining technology, low-cost large-scale production has been achieved. In recent years, MEMS accelerometers with noise lower than 1μg / Hz^(1 / 2), such as the SF1500 seismic accelerometer of Colibrys, Switzerland, the VectorSeis.ML21 digital three-axis MEMS seismic accelerometer of IONVA, and the capacitive MEMS seismic accelerometer of HP, USA, have been applied in the field of geophysics. It can be foreseen that high-precision MEMS accelerometers have broad application prospects in extreme environment, low-cost, and high-density geophysical detection, and have a trend of gradually replacing existing traditional geophysical instruments.

[0006] However, there is no precedent for the high-density arrangement of seismic accelerometers (such as one accelerometer every 1-3 meters) in the same borehole in underground arrays at home and abroad. Key technologies related to high-density observation of seismic accelerometers, such as segmented assembly of accelerometers, layered filling, sealing and waterproofing, synchronous acquisition, bus transmission, and multi-accelerometer fusion solution, have not been mentioned in the literature. Summary of the invention

[0007] In view of this, the present application provides a vertical drilling array strong earthquake observation device and an installation method thereof, which constructs a seismic acceleration observation array by densely arranging multi-level digital three-dimensional seismic acceleration probes at different depths in the same well, simplifies the installation and filling process, eliminates tube wave interference and azimuth deviation, and provides a continuous waveform observation record of three-dimensional acceleration of seismic motion with high signal-to-noise ratio characteristics, thereby realizing the full-process fine monitoring of seismic motion propagation from deep in the soil layer to the surface.

[0008] In a first aspect, the present application provides a vertical drilling array strong earthquake observation device, which adopts the following technical solution: A vertical drilling array strong earthquake observation device, comprising: a seismic acquisition station arranged on the surface, a plurality of digital three-dimensional seismic acceleration probes arranged vertically from the wellhead to the well bottom, an inter-stage connecting tube assembly for seismic isolation connected between adjacent digital three-dimensional seismic acceleration probes, and a grouting assembly arranged in the well along the well depth; Adjacent digital three-dimensional seismic acceleration probes and interstage connecting tube assemblies are connected via a joint assembly; The digital three-dimensional seismic acceleration probes at each level are electrically connected together, and the seismic acquisition station is electrically connected to the digital three-dimensional seismic acceleration probe near the wellhead.

[0009] By adopting the above technical solution, several levels of digital three-dimensional seismic acceleration probes are arranged step by step at different design depths of the same vertical drilling, and the arrangement distance between adjacent probes is not limited, together forming a linearly distributed seismic acceleration observation array, and real-time synchronously observing the near-field vibration acceleration waveform when the seismic wave propagates upward from the deep formation; The interstage connecting tube assembly is used for seismic isolation, effectively blocking the influence of tube waves propagating along the borehole, preventing signal cross-interference between the adjacent upper and lower digital three-dimensional seismic acceleration probes, and ensuring the quality of seismic signal acquisition. The grouting assembly is used to inject expansion cement mortar into the borehole to ensure that each digital three-dimensional seismic acceleration probe is fully coupled with the well wall.

[0010] Optionally, each level of the digital three-dimensional seismic acceleration probe includes a three-axis MEMS accelerometer and a straightening bracket assembly erected around the three-axis MEMS accelerometer; The triaxial MEMS accelerometer comprises a stainless steel outer cylinder, Glen heads located at both ends of the stainless steel outer cylinder, a three-dimensional MEMS acceleration integrated circuit board located inside the stainless steel outer cylinder, and a centering positioning plate for centering and fixing the three-dimensional MEMS acceleration integrated circuit board; The three-dimensional MEMS acceleration integrated circuit board comprises a control storage module, a collection module electrically connected to the control storage module, a timing module, a communication module and a power supply module.

[0011] By adopting the above technical solution, the straightening bracket assembly can form a larger cavity between the digital three-dimensional seismic acceleration probe and the borehole wall, so that the slurry can completely wrap the digital three-dimensional seismic acceleration probe, which can ensure that the digital three-dimensional seismic acceleration probe is fully coupled with the hole wall to form a good wave impedance matching, so that the seismic wave signal in the surrounding rock and soil can be transmitted to the probe without attenuation, and the MEMS accelerometer can accurately observe the seismic acceleration signal; The stainless steel outer cylinder and two Glen heads form a sealed chamber for encapsulating the three-dimensional MEMS acceleration integrated circuit board. Due to the solidity and durability of stainless steel, it can effectively protect the internal electronic components in the harsh underground environment; The control storage module is used to control the time calibration module and the communication module to independently complete the time calibration of the local clock, the reception and response of the host computer instructions. The control acquisition module is used to independently complete the acquisition, triggering, recording and uploading of the three-way acceleration signal. The power supply module is used to supply power to each module.

[0012] Optionally, the straightening bracket assembly includes a rotating body surrounded by a plurality of arc-shaped steel wires, flange basins located at the upper and lower ends of the rotating body, and an annular hoop located in the rotating body and connected to each arc-shaped steel wire, wherein the annular hoop holds the stainless steel outer cylinder of the three-axis MEMS accelerometer; X / Y direction identification marks having the same direction are arranged on the flange basin and the stainless steel outer cylinder.

[0013] By adopting the above technical solution, the annular hoop fixes the three-axis MEMS accelerometer, and the arc steel wire is welded to the upper and lower flange basins and the annular hoop to form a metal skeleton. When the slurry solidifies, the slurry, the well wall, the metal skeleton, and the stainless steel outer cylinder form a structural whole similar to reinforced concrete, which can ensure that the digital three-dimensional seismic acceleration probe is fully coupled with the hole wall, forming a good wave impedance matching, so that the seismic wave signal in the surrounding rock and soil can be transmitted to the probe without attenuation, and the three-axis MEMS accelerometer can accurately observe the seismic acceleration signal. The straightening bracket assembly can ensure that the Z-axis direction of the three-axis MEMS accelerometer is always parallel to the borehole axis direction, and at the same time prevent the three-axis MEMS accelerometer from being too eccentric, resulting in uneven slurry wrapping and affecting coupling.

[0014] Optionally, the inter-stage connecting cylinder assembly includes one connecting cylinder or multiple connecting cylinders connected in series; when there are multiple connecting cylinders, two adjacent connecting cylinders are connected together by a sleeve joint; The connecting tube comprises a connecting tube shell and a lightweight seismic isolation material filled in the connecting tube shell, a connecting tube multi-core cable is passed through the connecting tube shell, and both ends of the connecting tube shell are provided with X / Y direction identification marks; The three-dimensional MEMS acceleration integrated circuit board is electrically connected to the probe multi-core cable, and two ends of the probe multi-core cable are respectively extended from two ends of the stainless steel outer cylinder and are respectively electrically connected to the adjacent connecting cylinder multi-core cable.

[0015] By adopting the above technical solution, the outer diameter of the connecting tube is slightly smaller than the borehole diameter, and the interior of the connecting tube shell is filled with lightweight seismic isolation materials, which can not only realize the layered filling between the digital three-dimensional seismic acceleration probes of various levels, but also effectively serve as a seismic isolation layer between the digital three-dimensional seismic acceleration probes, eliminating the tube wave interference between adjacent digital three-dimensional seismic acceleration probes; The number of sections of the connecting tube is determined by the layout distance of the connected digital three-dimensional seismic acceleration probe and the design length of the connecting tube. When the interstage connecting tube assembly contains multiple sections of connecting tubes, the adjacent connecting tubes are respectively inserted into the two ends of the sleeve joint, first connected by instant glue, and then fixed by positioning screws to achieve the connection of the two adjacent sections of the connecting tube; during the connection process, by ensuring that the X / Y direction identification marks of the two adjacent connecting tubes are consistent, the three-axis assembly of all digital three-dimensional seismic acceleration probes can be ensured to be isotropic.

[0016] A multi-core cable is passed through the shell of the connecting tube, and its two ends can be connected to the adjacent seismic acceleration probe or the multi-core cable passed through the connecting tube through the watertight male and female plugs, respectively, to achieve electrical connectivity of the probes at each level. The digital three-dimensional seismic acceleration probe and inter-stage connecting tube assembly can be pre-made for easy transportation, and can also simplify the on-site installation process and ensure installation quality.

[0017] Optionally, the joint assembly includes a butt plug connecting the digital three-dimensional seismic acceleration probe and the connecting tube; The docking plug includes a plug shell with a base at one end, a seismic isolation damper is fixed on the base, the seismic isolation damper is connected to the end of the straightening bracket assembly, and the other end of the plug shell is open and used for inserting the connecting tube.

[0018] By adopting the above technical solution and setting up seismic isolation damping, the axial vibration transmission can be effectively blocked, the interference of the vertical tube wave of the connecting tube on the signal of the digital three-dimensional seismic acceleration probe can be eliminated, and the signal-to-noise ratio can be improved; The inner diameter of the opening end of the butt plug is slightly larger than the outer diameter of the connecting tube, which can ensure that the connecting tube is inserted into the opening end of the butt plug. The two are connected by instant adhesive and then fixed by positioning screws.

[0019] Optionally, the grouting assembly includes a grouting pipe made of plastic material and burst valves arranged at intervals along the length of the grouting pipe, a large C-shaped clamp is clamped on the connecting tube, an open spring clamp is provided on the side of the large C-shaped clamp away from the connecting tube, and the grouting pipe is clamped on the spring clamp.

[0020] By adopting the above technical solution, the large C-shaped clamp and the spring clamp are integrally arranged, the grouting pipe is clamped on the spring clamp, and the connecting tube is clamped on the large C-shaped clamp, so that the grouting pipe is buckled and fixed on the outer wall of the interstage connecting tube assembly. When sinking the hole, the grouting pipe can follow the interstage connecting tube assembly to sink to the bottom of the well; Along the length of the grouting pipe, multi-stage burst valves are set in sections to control the grouting pressure and flow rate to ensure uniform grouting. During the grouting process of the expansive cement mortar, the burst valves are opened in sequence from the bottom of the hole, and the slurry is squeezed and lifted to displace the water in the hole, so that the slurry fills all the gaps in the borehole, ensuring that the digital three-dimensional seismic acceleration probe, the interstage connecting tube assembly and the inner wall of the borehole are tightly coupled.

[0021] Optionally, the digital three-dimensional seismic acceleration probe and the connecting tube are both pre-prepared in an integrated manner.

[0022] By adopting the above technical solution, the assembly of each unit of the digital three-dimensional seismic acceleration probe and its internal circuit welding packaging, the assembly of each unit of the connecting tube and its internal circuit routing packaging, and the installation of the joint assembly and grouting assembly are all completed in advance in the factory, simplifying the cumbersome assembly process on site. The entire multi-core cable is divided into a probe multi-core cable and a connecting tube cable, which are routed and packaged in the inner cavity of the digital three-dimensional seismic acceleration probe and the interstage connecting tube assembly, respectively, to avoid friction damage to the cable due to cable exposure during transportation and installation.

[0023] Optionally, the seismic acquisition station includes a seismic acquisition station integrated circuit; The seismic acquisition station integrated circuit includes a seismic acquisition microprocessor, a pulse-per-second timing module, a clock synchronization module, a data transmission module, a power supply management module, a control panel, a memory and a communication module which are all electrically connected to the seismic acquisition microprocessor.

[0024] By adopting the above technical solution, the pulse-per-second timing module is connected to the external timing device, and receives the 1PPS pulse-per-second reference clock signal periodically sent by the external timing device in real time, and ensures that the local clock is synchronized with the reference clock through the phase-locked loop technology; The clock synchronization module is connected to one end of the two-core clock synchronization bus, and broadcasts and sends standard clock signals to the three-axis MEMS accelerometers in the digital three-axis seismic acceleration probes at all levels through the two-core clock synchronization bus; The data transmission module is connected to one end of a two-core data transmission bus, and exchanges data with the three-axis MEMS accelerometers in the digital three-dimensional seismic acceleration probes at each level through the two-core data transmission bus; The power supply management module supplies power to each module, and the communication module is connected to an external communication device to transmit earthquake observation data to the server through the external communication device.

[0025] Optionally, the seismic acquisition station is a master clock node, which is used to receive in real time the 1PPS pulse-per-second reference clock signal periodically sent by an external timing device, and synchronize the output standard clock with the reference clock through a clock synchronization module; Each level of the digital three-dimensional seismic acceleration probe is a slave clock node, which receives the standard clock signal output by the clock synchronization module in real time and keeps the local slave clock synchronized with the reference clock.

[0026] By adopting the above technical solution, the reference clock of the external timing device, the master clock of the seismic acquisition station and the slave clock of the digital three-dimensional seismic acceleration probe can be synchronized, thereby ensuring that the probe arrays at all levels synchronously collect the three-dimensional seismic acceleration signals of the soil layer around the well according to the reference clock provided by the external timing device.

[0027] In a second aspect, the present application provides a method for installing a vertical drilling array strong earthquake observation device, which adopts the following technical solution: A method for installing a vertical drilling array strong earthquake observation device, used for the vertical drilling array strong earthquake observation device, comprises the following steps: According to the observation design requirements, the drilling rig is called to drill at the site to be measured, and the wellbore is protected by the drilling casing. After the hole reaches the lowest buried depth required by the design, the drill rod is pulled out, and a temporary working platform is built near the wellhead to prepare the equipment and materials required for the installation of the vertical drilling array strong earthquake observation device; Transport the three-dimensional digital seismic acceleration probes of each level, the connecting tube components between each level, the grouting components and the joint components to the site respectively; Using wellhead tools, pull ropes and other auxiliary devices, the installation is carried out step by step. First, the first-level digital three-dimensional seismic acceleration probe is tied with a pull rope and sunk into the well, leaving the end above the wellhead, and ensuring that the probe X-axis points to the horizontal due east direction and the probe Y-axis points to the horizontal due north direction. Then, the wellhead tools are used to fix it, and the first-level interstage connecting tube assembly is connected through the joint assembly, and the grouting assembly is clamped on the first-level interstage connecting tube assembly; then, the second-level digital three-dimensional seismic acceleration probe is sunk into the well and connected to the upper end of the second-level interstage connecting tube assembly through the joint assembly, and the grouting assembly is clamped on the second-level interstage connecting tube assembly; during the connection process, ensure that the X / Y direction identification mark of each level of the digital three-dimensional seismic acceleration probe is consistent with the X / Y direction identification mark of the interstage connecting tube assembly, and fix it with positioning screws; In sequence, until all digital three-dimensional seismic acceleration probes, interstage connecting tube assemblies, grouting assemblies and joint assemblies are sunk into the hole; Install the seismic acquisition station, debug and test the working status of each level of probes and the integrity of data transmission, ensure that each level of probes works normally, and data transmission and clock synchronization are accurate; Connect the grouting assembly to the grouting pump and slowly lift the drilling casing; as the drilling casing slowly moves upward, use the grouting assembly to fully grout the pores between the multi-stage digital three-dimensional seismic acceleration probe, the inter-stage connecting tube assembly and the well wall.

[0028] In summary, the present application includes at least one of the following beneficial technical effects: 1. Seismic accelerometers can be densely arranged in the same borehole (e.g., a digital three-dimensional seismic accelerometer can be arranged every 3 meters), which can effectively solve the problems of scarce observation data and insufficient observation capabilities while reducing observation costs.

[0029] 2. Using bus design, all digital three-dimensional seismic acceleration probes in the same well share a multi-core cable, two cores for power supply, two cores for data transmission, and two cores for clock synchronization, which can effectively reduce observation costs and simplify installation processes.

[0030] 3. The connecting tube assembly has the following functions: 1) It is convenient for the splicing, assembly, disassembly and transportation of the digital three-dimensional seismic accelerometer, and can be accurately installed to the designed depth underground. 2) After splicing and assembly, the XYZ three-axis assembly of the digital three-dimensional seismic accelerometer inside all probes can be ensured to be isotropic. During the countersunk installation, because the whole set of devices has a large torsional stiffness, it can effectively prevent torsional deformation and ensure that there is no azimuth deviation between the MEMS accelerometers after the downhole installation of each level of probes. 3) The cable is routed inside the connecting tube assembly to avoid friction damage to the cable due to exposure during transportation and installation; 4) The interior of the connecting tube shell is filled with lightweight seismic isolation materials, which not only facilitates the layered filling between seismic accelerometers, but also effectively acts as a seismic isolation layer between seismic accelerometers to eliminate tube wave interference between adjacent probes. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the overall structure of the vertical drilling array strong earthquake observation device embodying the present application; Figure 2 It is a schematic diagram of the structure of the interstage connecting cylinder assembly embodying the present application; Figure 3 It is a structural schematic diagram of a digital three-dimensional seismic acceleration probe embodying the present application; Figure 4 is a schematic diagram of the structure of a three-axis MEMS accelerometer embodying the present application; Figure 5 is an exploded view of a righting bracket assembly embodying the present application; Figure 6 It is a module diagram of a three-dimensional MEMS acceleration integrated circuit board embodying the present application; Figure 7 It is a module diagram of a seismic acquisition station integrated circuit embodying the present application; Figure 8 is a schematic diagram of the clock synchronization bus topology embodying the present application; Fig. 9 It is a schematic diagram of the initial installation state of the vertical drilling array strong earthquake observation device of the present application; Fig.10 It is a schematic diagram of the installation state of the vertical drilling array strong earthquake observation device of the present application; Fig.11 It is a schematic diagram of the installation completion state of the vertical drilling array strong earthquake observation device of the present application.

[0032] Description of reference numerals: 1. Seismic acquisition station; 10. Digital three-dimensional seismic acceleration probe; 110. Three-axis MEMS accelerometer; 111. Stainless steel outer cylinder; 112. Glen head; 113. Three-dimensional MEMS acceleration integrated circuit board; 114. Centering positioning plate; 115. Probe multi-core cable; 120. Righting bracket assembly; 121. Rotating body; 122. Flange basin; 123. Annular hoop; 20. Interstage connecting cylinder assembly; 21. Connecting cylinder; 210. Connecting cylinder shell; 211. Lightweight seismic isolation material; 212. Connecting cylinder multi-core cable; 30. Grouting assembly; 31. Grouting pipe; 32. Burst valve; 33. Large C-shaped clamp; 331. Spring clamp; 40. Joint assembly; 41. Base; 42. Plug shell; 43. Seismic isolation damping; 50. Sleeve joint. DETAILED DESCRIPTION

[0033] The following is combined with Figure 1-Figure 11 This application is described in further detail.

[0034] The embodiment of the present application discloses a strong earthquake observation device for a vertical drilling array.

[0035] See also Figure 1 and Figure 2 A vertical drilling array strong earthquake observation device includes a plurality of digital three-dimensional seismic acceleration probes 10 arranged in a well from top to bottom, and an interstage connecting tube assembly 20 connected between two adjacent digital three-dimensional seismic acceleration probes 10. The interstage connecting tube assembly 20 includes one connecting tube 21 or a plurality of connecting tubes 21 connected in series. The number of connecting tubes 21 depends on the arrangement distance between adjacent probes. The plurality of digital three-dimensional seismic acceleration probes 10 together constitute a linearly distributed seismic acceleration observation array, which synchronously observes the near-field vibration acceleration waveform when the seismic wave propagates upward from the depth of the formation in real time.

[0036] When there are multiple connecting tubes 21, two adjacent connecting tubes 21 are connected together by a sleeve joint 50. The sleeve joint 50 is a hollow cylindrical tube with two ends open. The adjacent connecting tubes 21 are respectively inserted into the two ends of the sleeve joint 50, first connected by instant glue, and then fixed by positioning screws, so as to achieve a stable connection between the two adjacent connecting tubes 21 and provide waterproof performance. The connecting tube 21 and the sleeve joint 50 are provided with positioning screw holes corresponding to the positioning screws.

[0037] The connecting tube 21 includes a connecting tube shell 210 and a lightweight seismic isolation material 211 filled in the connecting tube shell 210. The lightweight seismic isolation material 211 can not only facilitate the layered filling between the digital three-dimensional seismic acceleration probes 10, but also effectively serve as a seismic isolation layer between adjacent digital three-dimensional seismic acceleration probes 10, thereby eliminating tube wave interference between adjacent probes.

[0038] A connecting tube multi-core cable 212 is passed through the connecting tube shell 210, and the connecting tube multi-core cables 212 of adjacent connecting tube shells 210 are plugged in by a watertight male connector and a watertight female connector, which is easy to assemble and has a waterproof function.

[0039] Adjacent digital three-dimensional seismic acceleration probes 10 and interstage connecting tube assemblies 20 are connected by a joint assembly 40 with waterproof performance. A seismic acquisition station 1 is arranged on the surface beside the wellhead, and the seismic acquisition station 1 is electrically connected to the digital three-dimensional seismic acceleration probe 10 near the wellhead. The digital three-dimensional seismic acceleration probes 10 of each stage are electrically connected together by cables, and the cables include a connecting tube multi-core cable 212 passing through the interstage connecting tube assembly 20, and the connecting tube multi-core cable 212 is electrically connected to the adjacent digital three-dimensional seismic acceleration probes.

[0040] The digital three-dimensional seismic acceleration probe 10 and the connecting tube 21 are both pre-prepared in an integrated manner.

[0041] A grouting assembly 30 is arranged along the depth direction of the well, which includes a grouting pipe 31 made of plastic material and a plurality of burst valves 32 arranged at intervals along the length of the grouting pipe 31. The grouting pipe 31 is clamped on a spring clamp 331, and a large C-shaped clamp 33 for clamping the connecting tube 21 is arranged in the middle of the spring clamp 331.

[0042] The grouting pipe 31 is made of hard plastic. When the digital three-dimensional seismic acceleration probe 10 and the interstage connecting tube assembly 20 are spliced, the grouting pipe 31 can be thrown to one side. After the interstage connecting tube assembly 20 is assembled, a large C-shaped clamp 33 has been clamped on the connecting tube 21, and the grouting pipe 31 is clamped into the spring clamp 331. Ensure that the grouting pipe 31 can go down to the bottom of the well when sinking.

[0043] The bursting valve 32 is used to control the pressure and flow rate during the grouting process to ensure uniform grouting. The bursting valve 32 can automatically release pressure when the grouting pressure is too high to ensure the safety of the system. The opening pressure of each level of the bursting valve 32 is different. The farther away from the wellhead, the smaller the opening pressure of the bursting valve 32. When grouting with expansive cement mortar, the bursting valve 32 is opened in sequence from the bottom of the hole, and the water in the hole is replaced by squeezing and lifting the slurry. The slurry fills all gaps in the well to ensure that the digital three-dimensional seismic acceleration probe 10, the interstage connecting tube assembly 20 and the inner wall of the well are fully coupled.

[0044] See also Figure 3 and Figure 4 Each level of the digital three-dimensional seismic acceleration probe 10 includes a three-axis MEMS accelerometer 110 and a straightening bracket assembly 120 erected around the three-axis MEMS accelerometer 110 .

[0045] The triaxial MEMS accelerometer 110 includes a hollow stainless steel outer cylinder 111, two ends of the stainless steel outer cylinder 111 are provided with Glen heads 112, a triaxial MEMS acceleration integrated circuit board 113 and two centering plates 114, all located in the stainless steel outer cylinder 111. The two centering plates 114 are arranged at intervals in the upper and lower parts to center the two ends of the triaxial MEMS acceleration integrated circuit board 113.

[0046] The three-axis MEMS acceleration integrated circuit board 113 of each three-axis MEMS accelerometer 110 is electrically connected to the probe multi-core cable 115. The two ends of the probe multi-core cable 115 extend from the two ends of the stainless steel outer tube 111 respectively, and are electrically connected to the adjacent connecting tube multi-core cable 212 respectively. It adopts a watertight male connector and a watertight female connector plug-in method, can be assembled on site, and has a waterproof function.

[0047] See also Figure 4 and Figure 5 The straightening bracket assembly 120 includes a rotating body 121 surrounded by a plurality of evenly arranged arc-shaped steel wires, a flange basin 122 located at the upper and lower ends of the rotating body 121, and an annular hoop 123 located in the rotating body 121 and connected to the upper and lower ends of each arc-shaped steel wire. The annular hoop 123 holds the stainless steel outer cylinder 111 of the three-axis MEMS accelerometer 110. The arc of the arc-shaped steel wire is bent toward the axis of the rotating body 121. Positioning screw holes are provided on the annular hoop 123 and the stainless steel outer cylinder 111, and are further fixed by positioning screws.

[0048] The flange basin 122 and the stainless steel outer cylinder 111 are both provided with X / Y direction identification marks in the same direction, and both ends of the connecting cylinder shell 210 are provided with X / Y direction identification marks to ensure the isotropic assembly of the three-axis digital three-axis seismic acceleration probe 10 .

[0049] The joint assembly 40 includes a butt plug connecting the digital three-dimensional seismic acceleration probe 10 and the connecting tube 21, which includes a plug shell 42 with a base 41 at one end, and a seismic isolation damper 43 with a conical end is fixed on the side of the base 41 away from the plug shell 42, and the conical end of the seismic isolation damper 43 is inserted into the opening of the flange basin 122. The other end of the seismic isolation damper 43 is cylindrical and is fixedly connected to the flange basin 122 and the base 41 by screws, and the other end of the plug shell 42 is open and used for inserting the connecting tube 21.

[0050] See also Figure 6The three-dimensional MEMS acceleration integrated circuit board 113 includes a control storage module, an acquisition module, a timing module, a communication module and a power supply module which are electrically connected to the control storage module. The control storage module is composed of an STM32 single-chip microcomputer, a memory and its peripheral circuits, and controls the acquisition module, the timing module and the communication module to independently complete the timing of the local clock, the reception and response of the host computer instructions, and the acquisition, triggering, recording and uploading of the three-dimensional acceleration signal.

[0051] The acquisition module is composed of an ultra-low noise density three-axis MEMS acceleration sensor and a front-end circuit. According to the local clock provided by the timing module, it collects the seismic acceleration signal of the soil layer around the probe, converts it into a digital quantity, and sends it to the control storage module. The X / Y / Z axes of the three-axis MEMS acceleration sensor are arranged in a Cartesian coordinate system. The timing module is connected to the two-core clock synchronization bus in the probe multi-core cable 115 to generate a high-precision local clock and send it to the control storage module. The communication module is connected to the two-core data transmission bus in the probe multi-core cable 115, which is used for data interaction between the control storage module and the off-hole seismic acquisition station 1. The power supply module is connected to the two-core power supply cable in the probe multi-core cable 115 to provide a wide voltage power supply for the control storage module.

[0052] The centering plate 114 can ensure that the Z-axis direction of the three-axis MEMS acceleration sensor is always parallel to the axial direction of the stainless steel outer cylinder 111. The three-axis MEMS acceleration integrated circuit board 113 is sealed and waterproofed by epoxy resin to improve its durability and waterproof performance. The Glen heads 112 at both ends lock the probe multi-core cable 115 to ensure a stable connection and excellent waterproof performance.

[0053] See also Figure 7 and Figure 8 The seismic acquisition station 1 includes a seismic acquisition station integrated circuit and an external packaging structure thereof. The seismic acquisition station integrated circuit board includes a seismic acquisition microprocessor, a second pulse timing module, a clock synchronization module, a data transmission module, a power supply management module, a control panel, a memory and a communication module which are all electrically connected to the seismic acquisition microprocessor.

[0054] The seismic acquisition microprocessor is composed of an STM32 single-chip microcomputer and its peripheral circuits. It controls the pulse-per-second timing module, clock synchronization module, data transmission module, power supply management module, control panel, memory and communication module, and independently completes the reception of 1PPS pulse-per-second reference clock signals, the issuance of standard clock signals, the synchronous acquisition of the drive probe array, and the reception, storage and remote transmission of seismic acceleration data.

[0055] The seismic acquisition station 1 is the master clock node, which is used to receive the 1PPS second pulse reference clock signal periodically sent by the external timing equipment in real time, and synchronize the local master clock output by the local temperature compensated quartz crystal resonator (clock synchronization module) with the reference clock through the phase-locked loop technology. The digital three-dimensional seismic acceleration probes 10 at all levels are slave clock nodes, which receive the local master clock signal output by the clock synchronization module in real time and synchronize the slave clock with the reference clock.

[0056] The pulse-per-second timing module is connected to external timing devices such as GPS / BD timing modules and NPT servers through the peripheral port, and receives the 1PPS pulse-per-second reference clock signal periodically sent by the external timing device in real time. Through the phase-locked loop technology, it ensures that the local clock is synchronized with the reference clock.

[0057] The clock synchronization module is connected to one end of the two-core clock synchronization bus, and broadcasts and sends a standard clock signal to the three-way MEMS acceleration integrated circuit board 113 in the probe array through the two-core clock synchronization bus.

[0058] The data transmission module is connected to one end of a two-core data transmission bus, and exchanges data with the three-dimensional MEMS acceleration integrated circuit board 113 in the probe array through the two-core data transmission bus.

[0059] The power supply management module is connected to a two-core power supply cable to provide wide voltage power supply to the three-way MEMS acceleration integrated circuit board 113 in the probe array through the two-core power supply cable.

[0060] The control panel is provided with an LCD screen, a power button, a working indicator light, a transmission indicator light, an RS232 interface, a USB interface, and an Ethernet interface.

[0061] The memory uses a large-capacity solid-state hard disk or a mounted SD card to store the seismic observation data uploaded by the probe array.

[0062] The communication module is connected to external communication devices such as 4G / 5G far-field wireless communication modules, 100M / 1G Ethernet wired communication modules, etc. through the peripheral port, and transmits seismic observation data to the server through the external communication devices.

[0063] The embodiment of the present application also discloses an installation method for the above-mentioned vertical drilling array strong earthquake observation device.

[0064] See also Fig. 9 , Fig.10 and Fig.11 A method for installing a vertical drilling array strong earthquake observation device, used for the vertical drilling array strong earthquake observation device, comprises the following steps: S1, according to the observation design requirements, the drilling rig is called to drill at the site to be tested, and the well casing is used to protect the well wall to prevent the hole from collapsing. After the hole reaches the lowest buried depth required by the design, the drill rod is pulled out, and a temporary working platform is built near the wellhead, and all the equipment and materials required for installation are prepared.

[0065] S2, customize the vertical drilling array strong earthquake observation device and transport it to the site in a disassembled form. The number of digital three-dimensional seismic acceleration probes 10, the length and number of the interstage connecting tube assemblies 20 between two adjacent levels of digital three-dimensional seismic acceleration probes 10 are customized and produced according to the monitoring design requirements. A customization example is as follows: the length of the digital three-dimensional seismic acceleration probe 10 and the connecting tube 21 are both 1m long, and a digital three-dimensional seismic acceleration probe 10 is installed every two connecting tubes 21, forming a probe array arrangement with a spacing of 3 meters.

[0066] S3, assemble each connection tube 21 in the inter-stage connection tube assembly 20 on the ground, first connect the connection tube multi-core cables 212 of two adjacent connection tubes 21 using a watertight male connector and a watertight female connector, and use a sleeve connector 50 to connect the two connection tubes 21, and then use waterproof instant glue and positioning screws to fix them. During the connection process, ensure that the X / Y direction identification marks of the two adjacent connection tubes 21 are consistent.

[0067] S4, using wellhead equipment, pull ropes and other auxiliary devices, the multi-stage digital three-dimensional seismic acceleration probe 10 and the inter-stage connecting tube assembly 20 are assembled and sunk into the well in a step-by-step installation manner.

[0068] Specifically, first tie the first-level digital three-dimensional seismic acceleration probe 10 with a drawstring, then sink it into the well, leaving the end above the wellhead, and ensure that the probe X-axis points to the horizontal due east direction and the probe Y-axis points to the horizontal due north direction, and then fix it with a wellhead tool. The drawstring is used to assist installation, prevent the structure from falling into the hole, and facilitate pulling out the device when it is stuck.

[0069] Next, the probe multi-core cable 115 and the connecting tube multi-core cable 212 are plugged together using a watertight male connector and a watertight female connector, and then the first-stage digital three-dimensional seismic acceleration probe 10 is connected to the first-stage interstage connecting tube assembly 20 using a connector assembly 40 and fixed using instant glue and positioning screws. During the connection process, ensure that the X / Y direction identification marks of the digital three-dimensional seismic acceleration probe 10 and the interstage connecting tube assembly 20 of each stage are consistent.

[0070] At the same time, a spring clamp 331 for clamping the grouting pipe 31 is installed on the connecting tube 21 and reinforced with rivets, and ensure that the end of the grouting pipe 31 used for exhaust is located at the bottom of the probe.

[0071] Slowly lower the pull rope, sink the connected interstage connecting tube assembly 20 and the grouting pipe 31 into the well, leave its port at the wellhead, fix it with wellhead equipment, and then assemble the second-stage digital three-dimensional seismic acceleration probe 10 and the second-stage interstage connecting tube assembly 20.

[0072] This is done sequentially until all the digital three-dimensional seismic acceleration probes 10, the interstage connecting tube assemblies 20, the grouting assemblies 30 and the joint assemblies 40 are sunk into the hole.

[0073] S5, install the seismic acquisition station 1, debug and detect the working status of each level of probes and the integrity of data transmission, ensure that each level of probes works normally, and the data transmission and clock synchronization are accurate.

[0074] S6, connect the grouting pipe 31 to the grouting pump, and slowly lift the drilling casing; as the casing slowly moves upward, use the grouting assembly 30 to fully grout the gaps between the digital three-dimensional seismic acceleration probe 10, the inter-stage connecting tube assembly 20 and the well wall, ensuring that each level of the digital three-dimensional seismic acceleration probe 10 is fully coupled and fixed to the hole wall. The grouting process requires strict control of pressure and flow to ensure uniform distribution of the slurry.

[0075] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A vertical drilling array strong earthquake observation device, characterized in that: include: A seismic acquisition station (1) disposed on the surface, a plurality of digital three-dimensional seismic acceleration probes (10) disposed vertically from the wellhead to the well bottom, an inter-stage connecting tube assembly (20) for seismic isolation connected between adjacent digital three-dimensional seismic acceleration probes (10), and a grouting assembly (30) disposed in the well along the well depth; Adjacent digital three-dimensional seismic acceleration probes (10) and interstage connecting tube assemblies (20) are connected via a joint assembly (40); The digital three-dimensional seismic acceleration probes (10) of each stage are electrically connected together, and the seismic acquisition station (1) is electrically connected to the digital three-dimensional seismic acceleration probe (10) near the wellhead.

2. The vertical drilling array strong earthquake observation device according to claim 1, characterized in that: Each level of digital three-dimensional seismic acceleration probe (10) comprises a three-axis MEMS accelerometer (110) and a straightening support assembly (120) erected around the three-axis MEMS accelerometer (110); The three-axis MEMS accelerometer (110) comprises a stainless steel outer cylinder (111), Glen heads (112) located at two ends of the stainless steel outer cylinder (111), a three-dimensional MEMS acceleration integrated circuit board (113) located inside the stainless steel outer cylinder (111), and a centering positioning plate (114) for centering and fixing the three-dimensional MEMS acceleration integrated circuit board (113); The three-dimensional MEMS acceleration integrated circuit board (113) comprises a control storage module, a collection module electrically connected to the control storage module, a time calibration module, a communication module and a power supply module.

3. The vertical drilling array strong earthquake observation device according to claim 2, characterized in that: The righting support assembly (120) comprises a rotating body (121) surrounded by a plurality of arc-shaped steel wires, flange basins (122) located at the upper and lower ends of the rotating body (121), and an annular hoop (123) located inside the rotating body (121) and connected to each of the arc-shaped steel wires, wherein the annular hoop (123) holds the stainless steel outer cylinder (111) of the three-axis MEMS accelerometer (110); X / Y direction identification marks with the same direction are provided on the flange basin (122) and the stainless steel outer cylinder (111).

4. The vertical drilling array strong earthquake observation device according to claim 2, characterized in that: The inter-stage connecting cylinder assembly (20) comprises one connecting cylinder (21) or a plurality of connecting cylinders (21) connected in series; when there are a plurality of connecting cylinders (21), two adjacent connecting cylinders (21) are connected together by a sleeve joint (50); The connecting tube (21) comprises a connecting tube shell (210) and a lightweight seismic isolation material (211) filled in the connecting tube shell (210); a connecting tube multi-core cable (212) is inserted into the connecting tube shell (210); and both ends of the connecting tube shell (210) are provided with X / Y direction identification marks; The three-dimensional MEMS acceleration integrated circuit board (113) is electrically connected to a probe multi-core cable (115), and two ends of the probe multi-core cable (115) extend from two ends of the stainless steel outer cylinder (111) and are electrically connected to adjacent connecting cylinder multi-core cables (212).

5. The vertical drilling array strong earthquake observation device according to claim 4, characterized in that: The joint assembly (40) comprises a butt plug for connecting the digital three-dimensional seismic acceleration probe (10) and the connecting tube (21); The docking plug comprises a plug shell (42) with a base (41) provided at one end, a seismic isolation damper (43) being fixed on the base (41), the seismic isolation damper (43) being connected to the end of the straightening bracket assembly (120), and the other end of the plug shell (42) being open and used for inserting the connecting cylinder (21).

6. The vertical drilling array strong earthquake observation device according to claim 4, characterized in that: The grouting assembly (30) comprises a grouting pipe (31) made of plastic material and burst valves (32) arranged at intervals along the length of the grouting pipe (31); a large C-shaped clamp (33) is clamped on the connecting tube (21); a spring clamp (331) with an opening is arranged on the side of the large C-shaped clamp (33) facing away from the connecting tube (21); and the grouting pipe (31) is clamped on the spring clamp (331).

7. The vertical drilling array strong earthquake observation device according to claim 4, characterized in that: The digital three-dimensional seismic acceleration probe (10) and the connecting tube (21) are both pre-prepared in an integrated manner.

8. The vertical drilling array strong earthquake observation device according to claim 1, characterized in that: The seismic acquisition station (1) comprises a seismic acquisition station integrated circuit; The seismic acquisition station integrated circuit includes a seismic acquisition microprocessor, a pulse-per-second timing module, a clock synchronization module, a data transmission module, a power supply management module, a control panel, a memory and a communication module which are all electrically connected to the seismic acquisition microprocessor.

9. The vertical drilling array strong earthquake observation device according to claim 8, characterized in that: The seismic acquisition station (1) is a master clock node, which is used to receive in real time the 1PPS pulse per second reference clock signal periodically sent by an external timing device, and synchronize the output standard clock with the reference clock through a clock synchronization module; Each level of the digital three-dimensional seismic acceleration probe (10) is a slave clock node, which receives the standard clock signal output by the clock synchronization module in real time and keeps the local slave clock synchronized with the reference clock.

10. A method for installing a vertical drilling array strong earthquake observation device, used for the vertical drilling array strong earthquake observation device according to any one of claims 1 to 9, characterized in that: Includes steps: According to the observation design requirements, the drilling rig is called to drill at the site to be measured, and the wellbore is protected by the drilling casing. After the hole reaches the lowest buried depth required by the design, the drill rod is pulled out, and a temporary working platform is built near the wellhead to prepare the equipment and materials required for the installation of the vertical drilling array strong earthquake observation device; The digital three-dimensional seismic acceleration probes (10) of each level, the connecting tube assemblies (20) between each level, the grouting assemblies (30) and the joint assemblies (40) are transported to the site respectively; Using wellhead tools, pull ropes and other auxiliary devices, a step-by-step installation method is adopted. First, the first-level digital three-dimensional seismic acceleration probe (10) is tied with a pull rope and sunk into the well, leaving the end above the wellhead, and ensuring that the probe X-axis points to the horizontal due east direction and the probe Y-axis points to the horizontal due north direction. Then, the wellhead tool is used to fix it, and the first-level interstage connecting tube assembly (20) is connected through the joint assembly (40), and the grouting assembly (30) is clamped on the first-level interstage connecting tube assembly (20); then, the second-level digital three-dimensional seismic acceleration probe (10) is sunk into the well and connected to the upper end of the second-level interstage connecting tube assembly (20) through the joint assembly (40), and the grouting assembly (30) is clamped on the second-level interstage connecting tube assembly (20); during the connection process, ensure that the X / Y direction identification mark of each level of the digital three-dimensional seismic acceleration probe (10) is consistent with the X / Y direction identification mark of the interstage connecting tube assembly (20); This is done sequentially until all the digital three-dimensional seismic acceleration probes (10), the interstage connecting tube assemblies (20), the grouting assemblies (30) and the joint assemblies (40) are sunk into the hole; Install the seismic acquisition station (1), debug and test the working status of each level of probes and the integrity of data transmission, ensure that each level of probes works normally, and that data transmission and clock synchronization are accurate; The grouting assembly (30) is connected to a grouting pump, and the drilling casing is lifted up; as the drilling casing moves upward, the grouting assembly (30) is used to perform full hole grouting on the pores between the multi-stage digital three-dimensional seismic acceleration probe (10), the inter-stage connecting tube assembly (20) and the well wall.

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