Emergency safety regulation and control system and method for underground excavation and close attachment construction of sandy gravel stratum

Abstract

The invention provides an emergency safety regulation and control system and method for sandy gravel stratum underground excavation and close attachment construction. The emergency safety regulation and control system comprises an emergency safety support, a deformation data acquisition module, a database, an analysis module, an intelligent regulation and control module, an information displayer and a jack controller. Comprising the following steps that deep hole grouting reinforcement construction is conducted on the sandy gravel stratum; excavating a sandy gravel stratum; an emergency safety support is erected; and grouting construction is conducted behind the primary support. The technical problem that in the sandy gravel stratum excavation process, the stratum and an overlying building structure are prone to instability can be solved.

Description

Technical Field

[0001] The present invention relates to the field of underground engineering technology, and in particular to an emergency safety control system and method for underground excavation and close-fitting construction in a sand and gravel stratum. Background Art

[0002] my country's rail engineering construction is experiencing rapid development. Rail transit construction often encounters numerous adverse geological conditions, such as gravel strata. These strata are characterized by loose structure, poor bonding ability, and weak self-stabilization capabilities, making them typical mechanically unstable strata. When underground excavation is conducted beneath related buildings in these strata, the unstable and prone to collapse poses a significant threat to the safety of the structure and personnel. Therefore, prior to excavating the gravel strata, grouting reinforcement must be performed to improve their self-stabilization capabilities. However, during the grouting reinforcement process, due to variations in the density of the gravel strata, the cement slurry may be too large to be injected into the dense gravel stratum, leading to backflow and upward bubbling of the grouting slurry. This results in poor grouting reinforcement effectiveness for the gravel stratum, making it difficult to ensure the stability of the gravel stratum during excavation, and putting the overlying building structures at risk of instability. Summary of the Invention

[0003] The purpose of the present invention is to provide an emergency safety control system and method for sand and gravel strata concealed excavation and close-fitting construction, which can solve the technical problem that the stratum and the overlying building structure are prone to instability during the excavation process of sand and gravel strata.

[0004] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: an emergency safety control system for underground excavation and close-fitting construction in sand and gravel strata, including an emergency safety support, a deformation data acquisition module, a database, an analysis module, an intelligent control module, an information display, and a jack controller; the deformation data acquisition module is used to obtain the settlement and deformation information of the overlying structure, and send the real-time data to the database and analysis module; the analysis module is used to make a preliminary judgment on the settlement of the overlying structure, generate deformation time, measurement time interval, cumulative settlement value, settlement rate value, and settlement increase / decrease value information and send them to the information display for display; the database is used to store settlement deformation information and control indication information; the intelligent control module is used to intelligently control the side support jacks of the emergency safety support, judge the trend of the actual settlement rate value, set the criteria of the intelligent control module, and the intelligent control module sends the acquired settlement deformation information and control indication information to the jack controller for actual operation; after obtaining the control indication information, the jack controller performs a graded control operation of the emergency safety support until the settlement deformation value of the structure is adjusted close to the original value.

[0005] Preferably, the emergency safety bracket includes a circular bracket bottom beam, a column mounting support is welded on the circular bracket bottom beam, a bracket column is provided on the column mounting support, a jack hinged fixing ring is installed on the outer surface of the bracket column, two jack hinged seats are symmetrically provided on the jack hinged fixing ring, the two jack hinged seats are rotatably connected to the ends of the two bracket side support arms, the transverse pull rod hinged supports of the two bracket side support arms are connected by a horizontally arranged pull rod length adjuster and the jack transverse pull rod, and the pull rod length adjuster is used to adjust the inclination angle of the bracket side support arm.

[0006] Preferably, the support side support arm includes a support side support pad, a universal joint transmission shaft connection piece, a side support jack and a transverse pull rod hinged support which are connected end to end in sequence.

[0007] Preferably, the deformation data acquisition module includes a laser rangefinder, which is fixed to the top of the bracket column through a bracket ranging steel plate platform; a high-strength energy-absorbing buffer pad is filled between the bottom of the column mounting support and the bracket column.

[0008] Preferably, the settlement deformation information stored in the database includes deformation time, original settlement value, settlement rate value, settlement increase / decrease value, and the control indication information stored in the database includes settlement rate value, cumulative settlement value, and original settlement value; the deformation data acquisition module, database, analysis module, intelligent control module, information display, and jack controller are connected to each other through a wireless communication network.

[0009] An emergency safety control method for underground excavation and close-fitting construction in a sand and gravel stratum comprises the following steps: Step 1: Deep hole grouting reinforcement construction in sand and gravel strata; Step 2: excavation of sand and gravel stratum; Step 3: Install emergency safety brackets; Step 4: Grouting construction behind the primary support.

[0010] Preferably, the step 1 comprises the following steps: Step 11: The surveyor measures the position of each grouting hole according to the design drawings and marks it. The surveyor fixes the drilling rig according to the drilling position, selects the corresponding drill rod for installation, and adjusts the position and inclination of the drilling rig and drill rod according to the inclination of the drilling hole. Step 12: insert the guide tube. The guide tube is laid out according to the designed position and angle. The gap between the guide tube and the grouting hole is sealed with a viscoplastic material at the hole opening. Step 13: Insert the deep hole drill rod into the guide tube according to the drilling direction and start drilling. During the drilling process, water is injected to cool the drill bit and flush out the drill cuttings. During the drilling construction, the inclination angle and depth of the drill hole are remeasured every time a certain distance is drilled until the hole depth reaches the designed value. Step 14: Adjust the ratio of the dual-liquid slurry according to the conditions of the sand and gravel formation to meet the grouting pressure control requirements; the slurry flow rate gradually decreases from the medium flow rate, and the grouting pressure gradually increases from the low pressure to the final grouting pressure, and maintains the pressure injection for 5 minutes, and the grouting is completed; during the grouting process, the grouting effect is "double-controlled" by using the grouting amount and grouting pressure values; when the grouting volume is large and the grouting pressure is small, the cement slurry concentration can be increased and the pressure can be continuously increased to the design requirement value.

[0011] Preferably, the step 2 comprises the following steps: Step 21: According to the existing construction conditions on site, set up a dewatering well to ensure that the water level of the sand and gravel stratum meets the construction conditions during the construction period; Step 22: Initial support installation for tunnel excavation. Manual excavation and earthwork transportation by equipment. According to the design plan for excavation of sand and gravel strata, initial support installation is carried out immediately on the excavation surface after excavation to protect the stability of the excavated strata.

[0012] Preferably, step 3 comprises the following steps: Step 31: Assemble the emergency safety support in the order of support columns, high-strength energy-absorbing cushions, circular support bottom beams, and column mounting brackets, and place the circular support bottom beams on the excavated sand and gravel stratum. Step 32: Connect the support side arms through the jack hinged fixing ring. The number of support side arms can be adjusted according to the working conditions. The number, support inclination angle and height of the support side arms should be adjusted according to the on-site working conditions. Then, use the jack transverse tie rod to connect the support side arms to each other. Adjust the length of the transverse tie rod through the tie rod length adjuster. The support side support pad is tightly fitted with the overlying structure of the excavation surface. Step 33: Adjust the supporting force of the side support jacks so that the support side support pads can provide support for the primary support structure and ensure stability during the excavation process of the sand and gravel stratum; Step 34: Place a laser rangefinder on the support distance measurement steel plate platform to measure the settlement and deformation of the top structure during the construction phase, providing data early warning services for project safety; Step 35: During the structural deformation process, the universal joint shaft connector can autonomously coordinate and change its angle. The side support pad fits tightly against the overlying structure of the excavation surface. The laser rangefinder on the support ranging steel plate platform continuously and accurately measures the settlement deformation of the top structure. The support strength of the support side support arm jack is intelligently adjusted according to the structural deformation trend to ensure the structural support effect.

[0013] Preferably, in step 4, after the primary support is completed, back grouting is carried out in time, the grouting holes are cleaned before grouting, and the grouting pipes are installed. The grouting should be injected from low to high, from waterless areas to water areas in sequence to facilitate dense filling and avoid dilution and segregation of the slurry by water.

[0014] The beneficial effects of the present invention are: This solution adopts a comprehensive grouting method of deep-hole grouting of sand and gravel + grouting behind the primary support to strengthen the stability of the sand and gravel stratum excavation process. The problem of poor grouting reinforcement effect of the sand and gravel stratum is avoided by the method of secondary grouting after excavation, thereby improving the effect of grouting reinforcement of the stratum. The present invention supports the base plate of the overlying structure by setting up an emergency safety bracket on the working surface, limits the deformation of the structure, and ensures the stability of the structure after excavation. The emergency safety bracket has a simple structure, is easy to process, and is easy to install and disassemble. It is highly practical and can adjust the height and number of the bracket side support arms according to different working conditions. The bracket side support arms of the emergency safety bracket of the present invention are provided with a universal transmission shaft connector that can monitor the deformation of the structure according to the settlement. The bracket side support pads can autonomously coordinate and change the angle. The control system can intelligently adjust the support strength of the bracket side support arm jack according to the deformation, thereby realizing intelligent control of the bracket support, increasing the engineering application scenarios of the bracket, and effectively solving the stability problem of the overlying related building structure during the close-fitting underpass construction. The method for intelligently controlling the supporting force of the jacks in a graded manner according to the settlement deformation rate index proposed in the present invention can dynamically control the settlement deformation of the structure and effectively control the jacks in a graded manner according to the settlement deformation rate index. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0016] Figure 1 This is a framework diagram of the emergency safety control system of the present invention.

[0017] Figure 2 It is a structural schematic diagram of the emergency safety bracket of the present invention.

[0018] Figure 3 It is a flow chart of the emergency safety control method of the present invention.

[0019] In the figure, 1. bracket side support arm; 101. bracket side support pad; 102. universal joint transmission shaft connector; 103. side support jack; 104. transverse pull rod hinged support; 2. laser rangefinder; 3. bracket ranging steel plate platform; 4. pull rod length adjuster; 5. jack transverse pull rod; 6. jack hinged seat; 7. jack hinged fixing ring; 8. bracket column; 9. column mounting support; 10. high-strength energy-absorbing buffer pad; 11. circular bracket bottom beam. DETAILED DESCRIPTION

[0020] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0021] The structures, proportions, sizes, etc. depicted in the drawings of this specification are only used to match the contents disclosed in the specification so as to facilitate understanding and reading by persons familiar with this technology. They are not intended to limit the conditions under which the present invention can be implemented and therefore have no substantive technical significance. Any structural modifications, changes in proportional relationships, or adjustments in size should still fall within the scope of the technical contents disclosed in the present invention without affecting the efficacy and objectives that can be achieved by the present invention.

[0022] At the same time, it should be noted that: unless otherwise defined, the technical terms or scientific terms used herein should be understood by people with ordinary skills in the technical field to which the invention belongs. The meaning of "multiple" used in the patent application specification and claims of the present invention is two or more; the orientation or position relationship indicated by the terms "upper", "lower", "left", "right", "front end", "rear end", etc. is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. Changes or adjustments to their relative relationships should also be regarded as the scope of implementation of the present invention without substantial changes in the technical content.

[0023] The present invention will be described in further detail below with reference to the embodiments and accompanying drawings.

[0024] The present invention discloses an emergency safety control system for underground excavation and close-fitting construction in sand and gravel strata. Figure 1 As shown, the embodiment includes an emergency safety support, a deformation data acquisition module, a database, an analysis module, an intelligent control module, an information display, and a jack controller. The deformation data acquisition module is used to obtain the settlement deformation information of the overlying structure and send the real-time data to the database and analysis module. The analysis module is used to make a preliminary judgment on the settlement of the overlying structure, generate deformation time, measurement time interval, cumulative settlement value, settlement rate value, settlement increase / decrease value information and send it to the information display for display; the database is used to store settlement deformation information and control instruction information. The intelligent control module is used to intelligently control the side support jack 103 of the emergency safety support, judge the trend of the actual settlement rate value, set the criteria of the intelligent control module, and the intelligent control module sends the acquired settlement deformation information and control instruction information to the jack controller for actual operation; after obtaining the control instruction information, the jack controller performs hierarchical control operations on the emergency safety support until the settlement deformation value of the structure is adjusted close to the original value.

[0025] The settlement deformation information stored in the database includes deformation time, original settlement value, settlement rate value, and settlement increase / decrease value; the control indication information stored in the database includes settlement rate value, cumulative settlement value, and original settlement value; the deformation data acquisition module, database, analysis module, intelligent control module, information display, and jack controller are communicated with each other through a wireless communication network.

[0026] like Figure 2 As shown, the emergency safety bracket includes a circular bracket bottom beam 11, a column mounting support 9 is welded on the circular bracket bottom beam 11, a bracket column 8 is provided on the column mounting support 9, a jack hinged fixing ring 7 is installed on the outer surface of the bracket column 8, and two jack hinged seats 6 are symmetrically provided on the jack hinged fixing ring 7. The two jack hinged seats 6 are rotatably connected to the ends of the two bracket side support arms 1, and the transverse pull rod hinge supports 104 of the two bracket side support arms 1 are connected by a horizontally arranged pull rod length adjuster 4 and a jack transverse pull rod 5. The pull rod length adjuster 4 is used to adjust the inclination angle of the bracket side support arm 1.

[0027] The support side support arm 1 includes a support side support pad 101, a universal joint transmission shaft connecting piece 102, a side support jack 103 and a transverse pull rod hinge support 104 which are sequentially connected end to end.

[0028] The deformation data acquisition module includes a laser rangefinder 2, which is fixed to the top of the bracket column 8 through a bracket ranging steel plate platform 3; a high-strength energy-absorbing buffer pad 10 is filled between the bottom of the column mounting support 9 and the bracket column 8.

[0029] like Figure 3 As shown, a method for emergency safety control of underground excavation and close-fitting construction in sand and gravel strata includes the following steps: Step 1: Deep hole grouting reinforcement construction in sand and gravel strata; Step 2: excavation of sand and gravel stratum; Step 3: Install emergency safety brackets; Step 4: Grouting construction behind the primary support.

[0030] The step 1 comprises the following steps: Step 11: The surveyor measures the position of each grouting hole according to the design drawings and marks it. The surveyor fixes the drilling rig according to the drilling position, selects the corresponding drill rod for installation, and adjusts the position and inclination of the drilling rig and drill rod according to the inclination of the drilling hole. Step 12: insert the guide tube. The guide tube is laid out according to the designed position and angle. The gap between the guide tube and the grouting hole is sealed with a viscoplastic material at the hole opening. Step 13: Insert the deep hole drill rod into the guide tube according to the drilling direction and start drilling. During the drilling process, water is injected to cool the drill bit and flush out the drill cuttings. During the drilling construction, the inclination angle and depth of the drill hole are remeasured every time a certain distance is drilled until the hole depth reaches the designed value. Step 14: Adjust the ratio of the dual-liquid slurry according to the conditions of the sand and gravel formation to meet the grouting pressure control requirements; the slurry flow rate gradually decreases from the medium flow rate, and the grouting pressure gradually increases from the low pressure to the final grouting pressure, and maintains the pressure injection for 5 minutes, and the grouting is completed; during the grouting process, the grouting effect is "double-controlled" by using the grouting amount and grouting pressure values; when the grouting volume is large and the grouting pressure is small, the cement slurry concentration can be increased and the pressure can be continuously increased to the design requirement value.

[0031] The step 2 comprises the following steps: Step 21: According to the existing construction conditions on site, set up a dewatering well to ensure that the water level of the sand and gravel stratum meets the construction conditions during the construction period; Step 22: Initial support installation for tunnel excavation. Manual excavation and earthwork transportation by equipment. According to the design plan for excavation of sand and gravel strata, initial support installation is carried out immediately on the excavation surface after excavation to protect the stability of the excavated strata.

[0032] The step 3 comprises the following steps: Step 31: Assemble the emergency safety support in the order of support column 8, high-strength energy-absorbing cushion 10, circular support bottom beam 11, and column mounting support 9, and place the circular support bottom beam 11 on the excavated sand and gravel stratum; Step 32: Connect the support side support arms 1 through the jack hinged fixing ring 7. The number of support side support arms 1 can be adjusted according to the working conditions. The number, support inclination angle and height of the support side support arms 1 should be adjusted according to the on-site working conditions. Then, use the jack transverse tie rod 5 to connect the support side support arms 1 to each other. Adjust the length of the transverse tie rod through the tie rod length adjuster 4. The support side support pad 101 is tightly fitted with the overlying structure of the excavation surface. Step 33: Adjust the supporting force of the side support jack 103 so that the support side support pad 101 can provide support for the primary support structure and ensure the stability of the sand and gravel stratum excavation process; Step 34: Place the laser rangefinder 2 on the bracket distance measurement steel plate platform 3 to measure the settlement and deformation of the top structure during the construction phase, providing data early warning services for project safety; Step 35, during the structural deformation process, the universal joint shaft connector 102 can autonomously coordinate and change the angle, the side support pad fits tightly against the overlying structure of the excavation surface, and the laser rangefinder 2 on the bracket ranging steel plate platform 3 continuously and accurately measures the settlement deformation of the top structure. The support strength of the bracket side support arm 1 jack is intelligently adjusted according to the structural deformation trend to ensure the structural support effect.

[0033] In step 4, after the primary support is completed, the back grouting is carried out in time. Before grouting, the grouting holes are cleaned and the grouting pipes are installed. The grouting should be injected from low to high, from waterless areas to water areas in sequence to facilitate dense filling and avoid dilution and segregation of the slurry by water.

[0034] In the specific implementation, taking the underground tunnel construction project of a certain city rail transit as an example, the excavation size of the underground section is 32.7m*24.1m×8.25m, that is, length*width*height; the excavation of the underground section is planned to be divided into 5 pilot tunnels, with upper and lower steps for excavation.

[0035] The top of the section is closely adjacent to an existing highway tunnel, and the construction process must ensure the normal operation of the existing highway tunnel. The underground excavation project is located in a particularly unfavorable sand and gravel stratum. The pebbles are mainly composed of quartzite and granite, are rounded and sub-rounded, and have a thickness of 2 to 4.1 meters. After excavation, the self-stabilization ability is very poor and it is prone to collapse. The overlying existing structure is greatly disturbed, and the structural settlement and deformation are difficult to control, posing a high risk of instability. The emergency safety control system and method for underground excavation construction in sand and gravel strata with close contact is adopted.

[0036] Step 1: Deep hole grouting reinforcement construction in sand and gravel formation 1. Measure and place the hole and put the drilling rig in place: The designed length of the borehole is 7.6m, with a horizontal spacing of 300mm and an external insertion angle of 1~3°. The surveyors measured the position of each grouting hole according to the design drawings and marked it. The drilling rig was fixed according to the drilling position, and the corresponding drill rod was selected for installation. The position and inclination of the drilling rig and drill rod were adjusted according to the inclination of the drilling hole. 2. Insert the guide tube: The guide tube is made of steel pipe and is laid out according to the designed position and angle. The gap between the guide tube and the grouting hole is sealed with viscoplastic material at the hole mouth. 3. Drilling: Before drilling, determine the direction and angle of the grouting reinforcement drilling hole in the sand and gravel formation, fix the position of the drill rod, and use a punch to drill the grouting hole. The diameter of the grouting hole is 63mm. Use a hole-drilling drill bit to drill holes in the corresponding position. The drilling angle of the grouting hole is 30°. The drilling angle refers to the angle between the drilling direction of the punch and the horizontal plane. The grouting hole is arranged in a plum blossom shape in the cross section; drill from the guide tube. When drilling, use low pressure and slow rotation. After drilling, use an angle measuring bracket to measure the drilling angle of the drill rod. Adjust the drilling angle of the drill rod according to the result to ensure the accuracy of the drilling direction and subsequent drilling.

[0037] 4. Grouting Slurry Preparation and Grouting: Cement slurry is preferred, with a water-cement ratio of 0.6-1. The grouting pressure is planned to be 0.5-1 MPa. A ball valve is installed at the orifice, and the grouting pipe is connected to the drill pipe. Grouting is carried out using a grouting pump. Initially, clear water or thin slurry is used to flow through the hole. At the end of grouting, thick slurry is used to seal the hole. Grouting is carried out from bottom to top according to the actual situation on site, and the final grouting pressure is controlled at 0.8 MPa.

[0038] Step 2: Excavation of sand and gravel stratum 1. Drainage: Based on the existing construction conditions, in-tunnel water collection and drainage is adopted. After 1m into the pilot tunnel, a 0.8m×1.2m×0.8m sump is excavated at the bottom of the primary support. A steel box is placed as a sump. A 7.5kW slurry pump is installed in the sump. Only the water pump replacement hole is retained on the upper sealing steel plate. The water pump is wrapped with a double-layer 60-mesh filter screen. An open drainage ditch is set at the tunnel face. The open excavation size is 100mm×100mm. Blind pipes with a diameter of 50mm are set on both sides of the bottom of the pilot tunnel as the excavation progresses. The blind pipes are made of PVC and have water inlet holes on the top. The blind pipes are connected to the open drainage ditch on the tunnel face. The seepage water on both sides and in front of the tunnel is introduced into the drainage ditches and blind pipes, and finally led to the sump and then pumped from the sump to the sedimentation steel box in the middle of the bottom plate. After sedimentation, it is pumped to the ground through a water pump and discharged into the municipal pipe network.

[0039] 2. Initial support installation for tunnel excavation: Each pilot tunnel is excavated using the up and down step method, with the step length controlled at 2m. Micro-excavators or scrapers are used as equipment. After excavation, a double-layer mesh of ∅8@150X150mm is used. The steel mesh is firmly connected to the positioning steel bars, and then sprayed concrete protection is immediately carried out. The primary support steel frame uses I28A I-beam steel frame. The excavation step and steel frame spacing are both 100cm. The inner and outer protective layers are 35mm. ∅26 ordinary bolts are used to connect the steel frame units. The steel frames are welded with ∅25 steel bars with a circumferential spacing of 1m for a double-layer arrangement. The steel frames are processed into frames outside the tunnel and pre-assembled. Locking foot anchor pipes are installed at the steel frame. The model is ∅42*3.5 hot-rolled steel pipe, the grouting pressure is 0.5~1MPa, and the length L=2m.

[0040] Step 3: Emergency safety bracket installation After the initial support is installed, an emergency safety support is erected on the primary support surface at the top of the sand and gravel stratum. The support can monitor the sinking displacement and stress conditions of the bottom plate of the overlying structure, reflect the settlement trend of the bottom plate structure, and adjust the support jack according to the settlement conditions to control the deformation of the bottom plate, thereby ensuring the safety of the bottom plate structure during construction.

[0041] 1) The emergency safety support is assembled in the following structural order: support column, high-strength energy-absorbing cushion, circular support bottom beam, column mounting support, etc. The circular support bottom beam is placed on the gravel stratum where the steel frame section is not set up on the excavation surface of the dark-cut pilot tunnel; 2) Connect the support side support arms through the jack hinged fixing ring. The number of support side support arms can be adjusted according to the working conditions. There are 2 support side support arms, which are supported at the primary concrete structure with a support inclination angle of 40° and a support side support arm height of 2m. Then use the jack transverse tie rod to connect each support side support arm to each other. Adjust the length of the transverse tie rod through the tie rod length adjuster. The support side support pad fits tightly with the overlying structure of the excavation surface.

[0042] 3) Adjust the supporting force of the side support jack to 5KN so that the support side support pad can provide support for the primary support structure and ensure the stability of the sand and gravel stratum excavation process; 4) A laser rangefinder was placed on the support distance measurement steel plate platform. At the initial stage of construction, the initial data for the distance between the overlying primary support structure and the laser rangefinder was 560 mm. The settlement and deformation measurement interval during construction was 4 hours, providing data early warning services for project safety. 5) During the structural deformation process, the universal joint shaft connector can autonomously coordinate and change its angle, and the side support pad fits tightly against the overlying structure of the excavation surface. The intelligent control module is set to issue a control instruction to the jack controller when the settlement deformation rate measured for three consecutive times continues to increase. The intelligent control module controls the side support jack to increase the supporting force. The support force increase criterion is 0.2 times the jack supporting force. If the settlement deformation rate measured for three consecutive times shows a downward trend, the control is stopped; otherwise, it continues to increase. The laser rangefinder on the bracket ranging steel plate platform continuously and accurately measures the settlement deformation of the top structure, and obtains the data sequence of structural settlement deformation as 560mm, 563.3mm, 567.3mm, and its settlement deformation rate is 3.3mm / 4h, 4.mm / 4h, and 4.5 / 4h, showing an increasing trend. Then the intelligent control instruction is started, and the supporting force of the jack is adjusted according to the amplitude of 5KN*0.2=5KN. The structural settlement deformation data during this period are 571.8mm, 576.5mm, 580.6mm, and 584.2mm, and its settlement deformation rate is 4.7mm / 4h, 4.1mm / 4h, 3.6mm / 4h, and 3.0mm / 4h. If the settlement deformation rate shows a continuous downward trend for three consecutive times, the current level of control is stopped; The support force increase criterion is set to 0.4 times the support force of the jack, and the support force of the jack is adjusted according to the amplitude of 5KN*0.4=2.0KN. When increasing by 2.0KN, 2*2.0KN, 3*2.0KN, 4*2.0KN, 5*2.0KN, and 6*2.0KN, the data of continuous and synchronous measurement of structural settlement and deformation are 579.7mm, 575.4mm, 571.4mm, 568.1mm, 564.6mm, and 561.4mm, which are close to the original structural settlement and deformation data. At this time, the support strength of the bracket side support arm jack can ensure the structural support effect.

[0043] It should be noted that the parts not described in detail in the above embodiments are all prior art.

[0044] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment, it is not intended to limit the present invention. Any technician familiar with the present profession can make slight changes or modifications to equivalent embodiments using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention should be covered by the protection scope of the present invention.

Claims

1. An emergency safety control system for underground excavation and close-fitting construction in sand and gravel strata, characterized by: It includes an emergency safety bracket, a deformation data acquisition module, a database, an analysis module, an intelligent control module, an information display, and a jack controller; the deformation data acquisition module is used to obtain the settlement deformation information of the overlying structure, and send the real-time data to the database and the analysis module; the analysis module is used to make a preliminary judgment on the settlement of the overlying structure, generate deformation time, measurement time interval, cumulative settlement value, settlement rate value, settlement increase / decrease value information and send it to the information display for display; the database is used to store settlement deformation information and control indication information; The intelligent control module is used to intelligently control the side support jack (103) of the emergency safety support, judge the trend of the actual settlement rate value, set the criteria of the intelligent control module, and the intelligent control module sends the acquired settlement deformation information and control instruction information to the jack controller for actual operation; After the jack controller obtains the control instruction information, it performs graded control operations on the emergency safety support until the settlement deformation value of the structure is adjusted close to the original value.

2. According to claim 1, an emergency safety control system for sand and gravel stratum underground excavation and close-fitting construction is characterized by: The emergency safety support comprises a circular support bottom beam (11), a column mounting support (9) is welded on the circular support bottom beam (11), a support column (8) is arranged on the column mounting support (9), a jack hinged fixing ring (7) is installed on the outer surface of the support column (8), two jack hinged seats (6) are symmetrically arranged on the jack hinged fixing ring (7), the two jack hinged seats (6) are rotatably connected to the ends of two support side support arms (1), and the transverse tie rod hinged supports (104) of the two support side support arms (1) are connected via a horizontally arranged tie rod length adjuster (4) and a jack transverse tie rod (5), and the tie rod length adjuster (4) is used to adjust the inclination angle of the support side support arm (1).

3. According to claim 2, an emergency safety control system for sand and gravel stratum dark excavation and close-fitting construction is characterized by: The support side support arm (1) comprises a support side support pad (101), a universal transmission shaft connection piece (102), a side support jack (103) and a transverse pull rod hinged support (104) which are sequentially connected end to end.

4. The emergency safety control system for sand and gravel stratum underground excavation and close-fitting construction according to claim 2 is characterized by: The deformation data acquisition module comprises a laser rangefinder (2), and the laser rangefinder (2) is fixed to the top of a support column (8) via a support distance measurement steel plate platform (3); a high-strength energy-absorbing buffer pad (10) is filled between the bottom of the column mounting support (9) and the support column (8).

5. The emergency safety control system for sand and gravel stratum underground excavation and close-fitting construction according to claim 1 is characterized by: The settlement deformation information stored in the database includes deformation time, original settlement value, settlement rate value, settlement increase / decrease value; the control indication information stored in the database includes settlement rate value, cumulative settlement value, and original settlement value; the deformation data acquisition module, database, analysis module, intelligent control module, information display, and jack controller are communicated and connected via a wireless communication network.

6. A method for emergency safety control of sand and gravel strata dark excavation close-fitting construction, applied to the emergency safety control system for sand and gravel strata dark excavation close-fitting construction according to any one of claims 1 to 5, characterized in that: The following steps are involved: Step 1: deep hole grouting reinforcement construction in sand and gravel strata; Step 2: excavation of sand and gravel strata; Step 3: Erection of emergency safety bracket; Step 4: Grouting construction behind the primary support.

7. The method for emergency safety control of sand and gravel stratum concealed excavation and close-fitting construction according to claim 6 is characterized by: The step 1 comprises the following steps: Step 11: The surveyor measures the position of each grouting hole according to the design drawings, marks it, fixes the drilling rig according to the drilling position, selects the corresponding drill rod for installation, and adjusts the position and inclination of the drilling rig and drill rod according to the inclination of the drilling hole; Step 12: insert the guide tube, lay the guide tube according to the designed position and angle, and use viscoplastic material to seal the gap between the guide tube and the grouting hole at the hole opening; Step 13, insert the deep hole drill rod into the guide tube according to the drilling direction for drilling, and inject water to cool the drill bit and flush out the drilling debris during the drilling process. During the drilling construction, the inclination angle and depth of the drilling hole are re-measured every time a certain distance is drilled until the hole depth reaches the designed value; Step 14: Adjust the ratio of double-liquid slurry according to the conditions of sand and gravel formations to meet the grouting pressure control requirements; the slurry flow rate gradually decreases from the medium flow rate, and the grouting pressure gradually increases from the low pressure to the final grouting pressure, and maintains the pressure injection for 5 minutes, and the grouting is completed; during the grouting process, the grouting effect is "double-controlled" by using the grouting amount and grouting pressure value; when the grouting volume is large and the grouting pressure is small, the cement slurry concentration can be increased, and the pressure can be continuously increased to the design requirement value.

8. The method for emergency safety control of sand and gravel stratum concealed excavation and close-fitting construction according to claim 6 is characterized by: The step 2 comprises the following steps: Step 21: According to the existing construction conditions on site, set up a precipitation well to ensure that the water level of the sand and gravel stratum meets the construction conditions during the construction period; Step 22: Initial support installation for tunnel excavation, manual excavation, earth transportation by equipment, according to the design plan for excavation in sand and gravel strata, initial support installation is carried out immediately on the excavation surface after excavation to protect the stability of the excavated strata.

9. The method for emergency safety control of sand and gravel stratum underground excavation and close-fitting construction according to claim 6 is characterized by: The step 3 comprises the following steps: Step 31, the emergency safety support is assembled in the structural order of the support column (8), the high-strength energy-absorbing buffer pad (10), the circular support bottom beam (11), and the column mounting support (9), and the circular support bottom beam (11) is placed on the excavated sand and gravel stratum; Step 32, the support side support arms (1) are connected by a jack hinged fixing ring (7), the number of the support side support arms (1) can be adjusted according to the working conditions, and the number, support inclination angle and height of the support side support arms (1) should be adjusted according to the on-site working conditions, and then the jack transverse tie rod (5) is used to connect the support side support arms (1) to each other, and the length of the transverse tie rod is adjusted by the tie rod length adjuster (4), and the support side support pad (101) is closely fitted with the overlying structure of the excavation surface; Step 33, adjusting the supporting force of the side support jack (103) so that the support side support pad (101) can provide supporting force to the primary support structure, thereby ensuring the stability of the sand and gravel stratum excavation process; Step 34: Place a laser rangefinder (2) on the bracket distance measurement steel plate platform (3) to measure the settlement deformation of the top structure during the construction phase, and provide data early warning services for engineering safety; Step 35, structural deformation process: the universal transmission shaft connector (102) can autonomously coordinate and change the angle, the side support pad is tightly fitted with the overlying structure of the excavation surface, and the laser rangefinder (2) on the support distance measurement steel plate platform (3) continuously and accurately measures the settlement deformation of the top structure. The support strength of the jack of the support side support arm (1) is intelligently adjusted according to the structural deformation trend to ensure the structural support effect.

10. The method for emergency safety control of sand and gravel stratum underground excavation and close-fitting construction according to claim 6 is characterized by: In step 4, after the initial support is completed, the back grouting is carried out in time, the grouting holes are cleaned before grouting, and the grouting pipes are installed. The grouting should be injected from low to high, from waterless areas to water areas in sequence to facilitate dense filling and avoid dilution and segregation of the slurry by water.

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