An assembled automatic jacking and resetting device for column piers and its construction method

Abstract

The present invention relates to the technical field of civil engineering reinforcement and underpinning transformation, and specifically relates to a column pier assembled automatic underpinning reset device and its construction method, which includes a number of upper steel brackets and lower steel brackets, respectively connected to the underpinning column pier. An elevating support column is fixed between each group of upper and lower steel brackets by a cantilever bolt; it also includes a liquid bag arranged in the middle of the cut-off underpinning column pier and connected to a pressure gauge and an automatic pressure-maintaining water supply device. Compared with the prior art, the advantages of the present invention are as follows: converting the underpinning settlement control displacement monitoring into pressure monitoring, which is less affected by the environment; introducing the latest second-order tooth contact interface at the connection surface between the underpinning bracket and the underpinning pier column, greatly improving the anti-shear slip ability; using a liquid bag for automatic pressure-maintaining water supply, with a small risk of oil leakage pollution and low long-term use cost; each column pier realizes the double insurance of liquid bag bearing and surrounding elevating temporary support bearing; the device has a simple structure, is convenient to assemble, has high construction efficiency and high safety.

Description

Technical Field

[0001] The present invention relates to the technical field of civil engineering reinforcement and replacement renovation, and specifically relates to a pier assembled automatic replacement and reset device and its construction method. Background Art

[0002] Structure replacement is a technology for changing the load transfer path of an engineering structure. With the development of China's construction industry gradually entering a stage that emphasizes both large-scale new construction and reinforcement and renovation, as well as the booming development of urban renewal construction activities, projects such as the reinforcement, displacement, large-space renovation, underground space development, and tunnel crossing of existing pile foundation buildings of existing engineering structures are increasing day by day. In the above projects, pier replacement is a key engineering technology that is widely applied.

[0003] Pier replacement technology usually transfers the vertical load originally transmitted from the pier to the foundation to a system composed of a replacement node and supporting components such as supports and jacks that are matched with it. During the replacement process, after the replacement node and the support under the node are completed, the pier often needs to be cut and separated from the foundation to achieve unloading and the transformation of the load transfer path.

[0004] Scholars and engineering technicians at home and abroad have conducted a large number of studies on pier replacement and designed a variety of replacement node forms. The most common one is the form of a beam embracing the column + post-implanted steel bars at the beam-column contact interface. This form of replacement node requires wet operations such as pouring concrete and then curing, and the construction period is relatively long. Therefore, institutions such as Hohai University have designed pre-stressed concrete assembled and steel structure assembled pier replacement nodes, conducted experimental studies, and carried out engineering pilot applications. These studies did not consider the settlement difference factor at the same time.

[0005] In order to ensure the safety of the upper structure when controlling uneven settlement of the replacement structure, based on the concept of active replacement, Shanghai Tianyan Building Displacement Engineering Company proposed the idea of superimposing vertical jacks in the movable support. However, the assembled units of these assembled replacement nodes are relatively large, the construction difficulty is high, and the dimensions need to be customized, and the adaptability to the column cross-section shape is poor, which greatly increases the project cost. Therefore, new types of assembled replacement node forms with simple structures and operations should be further developed.

[0006] When there is synchronous integrated replacement of multiple piers, the automatic adjustment of settlement difference in active replacement projects often uses a PLC (programmable logic controller) system. This system has high standby energy consumption and costs. Especially when the number of replacement piers is small and the load-bearing time period of the replacement structure is long, the poor cost performance is more obvious. Therefore, a new type of automatic settlement difference control system with low cost and simple structure should be developed.

[0007] Common temporary supports in the structural underpinning system include steel columns, hydraulic jacks, etc. Displacement sensors are used to monitor settlement, and after feedback, commands are issued to adjust the height of the temporary support. However, at the construction site, displacement sensors are easily affected by the environment, thus affecting the settlement difference control effect. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a pier prefabricated automatic underpinning and reset device with simple structure, convenient construction, high efficiency and low pollution, and its construction method.

[0009] To achieve the above object, a pier prefabricated automatic underpinning and reset device is designed, which includes several groups of upper steel brackets and lower steel brackets. The upper steel brackets and lower steel brackets are connected to the underpinning pier. An elevating support column is fixed between each group of upper steel brackets and lower steel brackets with a cantilever bolt; a liquid bladder is also included, which is arranged in the middle of the underpinning pier after cutting. The liquid bladder is connected to a pressure gauge and an automatic pressure maintaining water supply device. The periphery of the liquid bladder is assembled with a casing and constrained by a hoop to form an integral body.

[0010] Preferably, several groups of upper steel brackets and lower steel brackets are fixed to the underpinning pier through shear bolts of the brackets and steel plates with second-order teeth, and then tightened by several groups of Hualan screws hooked on the anchor rings of the steel brackets.

[0011] Preferably, the upper steel bracket or the lower steel bracket is composed of an H-shaped steel with unequal flange lengths, a steel plate with second-order teeth, and prefabricated stiffeners. The side of the steel plate with second-order teeth connected to the H-shaped steel is a vertical plane, and the contact surface with the column surface is a toothed surface, which is provided with a first-order large tooth and several groups of second-order small teeth; reserved grooves are provided on the upper and lower flange plates on both sides of the web for installing stiffeners, and several groups of anchor rings are welded on both sides of the web near the edge from top to bottom.

[0012] Preferably, the elevating support column is composed of a steel spiral core barrel and a steel spiral sleeve, and the two are nested together through screw threads. The upper end plate of the steel spiral core barrel is suspended on the lower flange of the upper steel bracket through a support suspension bolt. A loading rod hole is provided at the lower part of the steel spiral sleeve, and a loading rod is inserted into it.

[0013] Preferably, the prefabricated casing is composed of a group of L-shaped steel casing units. Both sides are provided with upper and lower semi-circular notches. Multiple rubber protrusions are provided on the outer side of the vertical plate from top to bottom. The whole group of L-shaped steel casing units are in contact with each other to form a closed casing. There is no contact between the inner circumference of the casing and the surface of the underpinning pier. The upper part of the rubber protrusion is a hoop.

[0014] A construction method for a pier prefabricated automatic underpinning and reset device is as follows:

[0015] 1) Place cutting lines within the designed height of the pier underpinning. The distance between the cutting lines matches the height of the liquid bladder;

[0016] 2) Polish the surface of the pier at the upper and lower adjacent parts outside the pier cutting area, and the shape is basically consistent with the shape of the steel bracket with second-order teeth;

[0017] 3) Apply cement mortar with a strength not lower than that of the pier concrete;

[0018] 4) Install the upper and lower steel brackets, fix them with expansion bolts or anchor bolts, and keep the lower surface horizontal;

[0019] 5) Install the Hualan screws and tighten them to assemble the upper and lower steel brackets into two underpinning platforms; 6) Install lifting support columns between each group of upper and lower steel brackets. The upper end plate is suspended under the upper steel bracket with suspension bolts, and load rods are inserted into the loading rod holes of the steel screw sleeves one by one to adjust the height until it is tightened;

[0020] 7) Pass the static cutting wire saw through the gap of the support column to cut the pier; after cutting, put a hoop with a matching size, which can be temporarily fixed in the reserved sections at the upper and lower ends of the pier;

[0021] 8) Select a liquid bag matching the size of the pier, place it in the pier cutting area, and then connect the pressure gauge, water supply and drainage valve and the pressure maintaining water supply device;

[0022] 9) Fill with water and test the pressure: Install a displacement gauge between the upper and lower column ends, and then fill the high-pressure liquid bag with water and pressurize it until there is a sign of upward movement of the upper column end, and then relieve the pressure;

[0023] 10) Weigh and measure the pressure: Loosen the surrounding lifting support columns. If the upper column shows signs of sinking, pressurize the liquid bag to supply water and push the upper column end back to the original elevation. Then this pressure is the target value for maintaining the water pressure.

[0024] 11) Install the casing: First, place the casing unit around the underpinning pier along the pre-placed hoop, adjacent to each other. Then lower the placed hoop. When it encounters an obstacle at the rubber convex, increase the downward force of the hoop. After the rubber convex deforms, the lower hoop can pass through the rubber convex of this layer. In this way, there is a hoop installed above each corresponding rubber convex; continue to squeeze the hoop towards the rubber convex. When there is a feeling of tightening the hoop, stop squeezing the hoop;

[0025] 12) Tighten all the supports again, and the equipment is in the automatic standby state.

[0026] Preferably, the method further includes the state adjustment of the lifting support column:

[0027] 1) In the case of settlement or shutdown of the underpinning column, the standby state of the lifting support column is to tighten the upper and lower steel brackets. When the column settles, the water pressure measured by the pressure gauge decreases, and the pressure maintaining water supply device automatically adjusts the water supply to ensure that the upper column returns to the original elevation state. Then adjust the lifting support columns one by one to make them extend to the tightened state;

[0028] 2) In the settlement and heave condition of the underpinning column, the standby state of the lifting support column is the unloaded state.

[0029] Compared with the prior art, the advantages of the present invention are as follows:

[0030] 1. Convert the displacement monitoring of underpinning settlement control into pressure monitoring with less environmental influence;

[0031] 2. Introduce the latest second-order tooth contact interface at the connection surface between the underpinning bracket and the underpinning pier column, greatly improving the anti-shear slip ability;

[0032] 3. Adopt liquid capsule automatic pressure maintenance and water supply, effectively solving the problems of high risk of oil leakage pollution and high long-term use cost of the PLC system;

[0033] 4. For each column pier, double insurance of liquid capsule load bearing and surrounding lifting temporary support load bearing is achieved;

[0034] 5. The device has a simple structure, is convenient for assembly, has high construction efficiency and high safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 is the elevation view of the system installation state of the reset device provided by the present invention;

[0036] Figure 2 is the cross-sectional view of the bracket installation of the reset device provided by the present invention;

[0037] Figure 3 is the elevation view of the bracket structure of the reset device provided by the present invention;

[0038] Figure 4 is the enlarged view of the lifting support of the reset device provided by the present invention;

[0039] Figure 5 is the cross-sectional view of the installation of the casing liquid capsule of the reset device provided by the present invention;

[0040] Figure 6 is the elevation view of the casing wall unit of the reset device provided by the present invention.

[0041] In the figure:

[0042] 1. Underpinning column pier; 2. Upper steel bracket; 3. Lower steel bracket; 4. Lifting support column; 5. Casing; 6. High-pressure liquid capsule; 7. Pressure gauge; 8. Pressure maintenance water supply device; 9. Hualan screw; 10. Bracket shear bolt; 11. Support suspension bolt; 12. Ferrule.

[0043] 2-1. H-shaped steel with unequal flange lengths; 2-2. Steel plate with second-order teeth; 2-3. First-order large teeth; 2-4. Second-order small teeth; 2-5. First bolt hole; 2-6. Anchor ring; 2-7. Reserved groove; 2-8. Assembled stiffener; 2-9. Second bolt hole;

[0044] 4-1. Steel spiral core tube; 4-2. Steel spiral sleeve; 4-3. Bolt hole 3; 4-4. Loading rod hole; 4-5. Loading rod;

[0045] 5-1. L-shaped steel guard plate unit; 5-2. Semi-circular notch; 5-3. Rubber convexity. Specific implementation mode

[0046] The present invention will be further described below with reference to the accompanying drawings. The structure and principle of the present invention are very clear to those skilled in the art. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0047] As Figure 1 shown, the present invention discloses a column pier assembled automatic jacking and resetting device, which comprises a plurality of groups of upper steel corbels, lower steel corbels, lifting support columns, assembled casings, high-pressure liquid bags, pressure gauges, and an automatic pressure-keeping water supply device.

[0048] A plurality of groups of upper steel corbels and lower steel corbels are fixed on the column pier to be jacked through corbel shear bolts and steel plates with second-order teeth, and then tightened by a plurality of groups of Hualan screws hooked on the anchor rings of the steel corbels. A lifting support column is fixed between each group of upper steel corbels and lower steel corbels by a cantilever bolt. The lifting support column is composed of a steel spiral core tube and a steel spiral sleeve, and the two are nested together through screw threads. The upper end plate of the steel spiral core tube is suspended on the lower flange of the upper steel corbel through a support suspension bolt. A loading rod hole is provided at the lower part of the steel spiral sleeve, and a loading rod is inserted. Rotate the loading rod until it is tightened, and it is easy to realize the height adjustment.

[0049] The upper steel corbel or the lower steel corbel is composed of an H-shaped steel with unequal flange lengths, a steel plate with second-order teeth, and an assembled stiffener. The side of the steel plate with second-order teeth connected to the H-shaped steel is a vertical plane, and the contact surface with the column surface is a toothed surface, which is provided with a first-order large tooth and a plurality of groups of second-order small teeth; Reserved grooves are provided on the upper and lower flange plates on both sides of the web for installing stiffeners, and a plurality of groups of anchor rings are welded on both sides of the web outside the edge from top to bottom.

[0050] The main function of the anchor ring is that when a group of steel corbels are assembled, they can be connected by Hualan screws between two by two. Tighten the Hualan screws, and prestress can be applied to the group of jacking corbels, thereby improving the stability and reliability of the steel corbels when stressed. The latest scientific research results are introduced at the contact surface between the steel corbel and the column pier to be jacked, and the force transmission performance of the second-order tooth contact interface is better.

[0051] The adjustment of the support height of the spiral nested device belongs to mature technology. Due to the existence of hydraulic jacks, it is rarely used at the engineering site. However, when a hydraulic jack is used as a temporary support, the equipment is affected by leakage and is prone to pressure loss. Moreover, when multiple jacks are started synchronously, a PLC synchronous displacement control system is often required.

[0052] To ensure that there is sufficient contact area between the steel bracket and the column surface, first grind the surface of the column pier at the upper and lower adjacent parts outside the cutting area of the column pier, and the shape basically matches the shape of the steel plate with second-order teeth 2-2 in the steel bracket; apply 2-3 mm thick cement mortar to ensure the contact surface is dense, and the mortar strength is not lower than the concrete strength of the column pier.

[0053] After the temporary support is tightened, the column pier is cut; select a matching high-pressure liquid bag according to the size of the cut section and install it in the space after partial cutting of the column pier, and the periphery is basically flush with the outer edge line of the column pier.

[0054] The liquid bag is arranged in the middle of the column pier to be underpinning after cutting. The liquid bag is connected to a pressure gauge and an automatic pressure-maintaining water supply device. The periphery of the liquid bag is assembled with a casing and constrained by a hoop to form an integral body.

[0055] The assembled casing is composed of a group of L-shaped steel casing units. There are two upper and lower semi-circular notches on both sides. There are multiple rubber protrusions on the outside of the vertical plate from top to bottom. The whole group of L-shaped steel casing units are in contact with each other to form a closed casing. Its inner diameter is 10-20 mm larger than the diameter of the column pier to be underpinning, and the height extends upward and downward from the cutting area of the column pier by no less than 50 mm; there is no contact between the inner circumference of the casing and the surface of the column pier to be underpinning, and the minimum gap is not less than 2 mm. The upper part of the rubber protrusion is a hoop, and the outer diameter of the figure formed by the vertices of the rubber protrusions at the same elevation is more than 2 mm larger than the inner diameter of the hoop.

[0056] The setting of the casing is mainly to prevent the liquid bag from deforming greatly around, which may lead to failure in controlling the vertical displacement. The semi-circular notch is a reserved pipeline port. After two adjacent L-shaped casing units are spliced, a round hole is formed; the connecting pipe of the pressure-maintaining water supply equipment is connected to the liquid bag through this pipeline port.

[0057] The size and shape of the casing unit should consider the cross-sectional shape of the column pier. After the column is cut and before the liquid bag is installed, several hoops are first sleeved. After the airbag is restarted, the casing can be assembled. When assembling, first place the pre-placed hoops to place the casing units around the column pier to be underpinning in a circle, adjacent to each other, and then lower the placed hoops. When encountering obstacles when reaching the rubber protrusions, increase the downward hoop force. After the rubber protrusions are deformed, the following hoops can pass through the rubber protrusions of this layer. In this way, there is a hoop installed above each corresponding rubber protrusion. Continue to squeeze the hoop towards the rubber protrusion. When there is a feeling of tightening the hoop, stop squeezing the hoop.

[0058] Water filling and pressure testing: Install a displacement gauge with an accuracy of not less than 0.1 mm between the upper and lower column ends, and then fill the high-pressure liquid bag with water and pressurize it until there is a sign of upward movement at the upper column end. Check whether there is leakage, and whether the working conditions of the pressure gauge, valve, etc. are normal; then relieve the pressure, and the pressure relief amplitude shall not be less than 20% of the pressure test.

[0059] Weighing and pressure measurement: Loosen the four surrounding lifting support columns 4, and there is a sign of sinking of the upper column, and the maximum sinking is not more than 1 mm; pressurize the liquid bag to supply water and push the upper column end back to the original elevation, then this pressure is the target value for maintaining water pressure.

[0060] The construction method of the pier prefabricated automatic jacking and reset device is characterized in that the method is specifically as follows:

[0061] 1) Place cutting lines within the designed height of the pier jacking, and the distance between the cutting lines matches the height of the liquid bag;

[0062] 2) Grind the surface of the pier at the upper and lower adjacent parts outside the pier cutting area, and the shape basically matches the shape of the steel corbel with a second-order tooth plate;

[0063] 3) Apply cement mortar, and the mortar strength shall not be lower than the strength of the pier concrete;

[0064] 4) Install the upper and lower steel corbels, fix them with expansion bolts or anchor bolts, and keep the lower surface horizontal;

[0065] 5) Install the Hualan screws, tighten them, and assemble the upper and lower steel corbels into two jacking platforms;

[0066] 6) Install lifting support columns between each group of upper and lower steel corbels. The upper end plate is suspended under the upper steel corbel with a suspension bolt, and insert the loading rod into the loading rod hole of the steel screw sleeve one by one to adjust the height until it is tightened;

[0067] 7) Pass the static cutting wire saw through the gap of the support column to cut the pier; after cutting, place a hoop with a matching size, which can be temporarily fixed in the reserved sections at the upper and lower ends of the pier;

[0068] 8) Select a liquid bag that matches the size of the pier, place it in the pier cutting area, and then connect the pressure gauge, the water supply and drainage valve, and the pressure maintaining water supply device;

[0069] 9) Water filling and pressure testing: Install a displacement gauge with an accuracy of not less than 0.1 mm between the upper and lower column ends, and then fill the high-pressure liquid bag with water and pressurize it until there is a sign of upward movement at the upper column end. Check whether there is leakage, and whether the working conditions of the pressure gauge, valve, etc. are normal. Then relieve the pressure, and the pressure relief amplitude shall not be less than 20% of the pressure test;

[0070] 10) Weighing and pressure measurement: Loosen the lifting support columns around. If there is a sign of the upper column sinking and the maximum sinking is no more than 1 mm, pressurize the liquid bladder to supply water and push the upper column end back to the original elevation. Then this pressure is the target value for water pressure maintenance.

[0071] 11) Install the casing: First, place the pre - installed collar around the casing unit along the column pier to be underpinned in a circle, adjacent to each other. Then lower the placed collar. When encountering an obstacle at the rubber protrusion, increase the downward force of the collar. After the rubber protrusion deforms, the lower collar can pass through the rubber protrusion of this layer. In this way, there is a collar installed above each corresponding rubber protrusion; continue to squeeze the collar towards the rubber protrusion. When there is a feeling of tightening, stop squeezing the collar.

[0072] 12) Tighten all the supports again, and the equipment is in the automatic standby state.

[0073] The lifting support columns also have state settings to adapt to two different working conditions, namely the settlement or shutdown condition of the column to be underpinned and the settlement and uplift condition of the column to be underpinned.

[0074] 1) In the settlement or shutdown condition of the column to be underpinned, the standby state of the lifting support columns is to tightly support the upper and lower steel corbels. When the column settles and the water pressure measured by the pressure gauge decreases, the pressure - maintaining water supply device automatically adjusts the water supply to ensure that the upper column returns to the original elevation state, and then adjust each lifting support column one by one to make it extend to the tight - support state. 2) In the settlement and uplift condition of the column to be underpinned, the standby state of the lifting support column 4 is the unloaded state, and the distance between the lower end plate of the steel spiral sleeve and the top flange of the lower corbel is 1 - 2 mm.

[0075] The test data of the pressure gauge are archived in real - time for future reference, and the monitoring personnel set regular inspections of the pressure change records at intervals not exceeding 24 hours.

[0076] As described above, it is only the specific implementation manner of this invention, but the protection scope of this invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by this invention, according to the technical solution and new concept of this invention, makes equivalent substitutions or changes, and should be covered within the protection scope of this invention.

Claims

1. An assembled automatic jacking and resetting device for pier, comprising several groups of upper steel brackets and lower steel brackets, the upper steel brackets and the lower steel brackets are connected to the jacked pier, and it is characterized in that One lifting support column is fixed between each group of upper steel bracket and lower steel bracket with a cantilever bolt; further comprising a liquid bag, which is arranged in the middle of the cut-off column pier to be underpinned. The liquid bag is connected with a pressure gauge and an automatic pressure-maintaining water supply device. The periphery of the liquid bag is assembled with a casing and constrained by a hoop to form an integral whole; the several groups of upper steel brackets and lower steel brackets are fixed to the column pier to be underpinned through bracket shear bolts and steel plates with second-order teeth, and then tightened by several groups of Hualan screws hooked on the anchor rings of the steel brackets; the upper steel bracket or the lower steel bracket is composed of an H-shaped steel with unequal flange lengths, a steel plate with second-order teeth, and an assembled stiffener. The side of the steel plate with second-order teeth connected to the H-shaped steel is a vertical plane, and the contact surface with the column surface is a toothed surface, which is provided with a first-order large tooth and several groups of second-order small teeth; reserved grooves are arranged on the upper and lower flange plates on both sides of the web for installing stiffeners, and several groups of anchor rings are welded on both sides of the web near the edge from top to bottom; the lifting support column is composed of a steel spiral core barrel and a steel spiral sleeve, and the two are nested together through screw threads. The upper end plate of the steel spiral core barrel is suspended on the lower flange of the upper steel bracket through a support suspension bolt, and a loading rod hole is arranged at the lower part of the steel spiral sleeve, and a loading rod is inserted into it; the assembled casing is composed of a group of L-shaped steel casing units. Both sides are provided with upper and lower semi-circular notches, and multiple rubber protrusions are arranged on the outside of the vertical plate from top to bottom. The whole group of L-shaped steel casing units are in contact with each other to form a closed casing. There is no contact between the inner periphery of the casing and the surface of the column pier to be underpinned, and the upper part of the rubber protrusion is a hoop; 2. A construction method using the assembled automatic jacking and resetting device for pier as described in claim 1, and it is characterized in that The method is as follows: 1) Place cutting lines within the design height of the column pier underpinning. The distance between the cutting lines matches the height of the liquid bag; 2) Grind the surface of the column pier at the upper and lower adjacent parts outside the cutting area of the column pier, and the shape basically matches the shape of the steel plate with second-order teeth in the steel bracket; 3) Apply cement mortar, and the strength of the mortar is not lower than the strength of the column pier concrete; 4) Install the upper and lower steel brackets, and fix them with expansion bolts or anchor bolts, and keep the lower surface horizontal; 5) Install Hualan screws and tighten them to assemble the upper and lower steel brackets into two underpinning platforms; 6) Install a lifting support column between each group of upper and lower steel brackets. The upper end plate is suspended under the upper steel bracket with a suspension bolt, and a loading rod is inserted into the loading rod hole of the steel spiral sleeve one by one to adjust the height until it is tightened; 7) Pass a static cutting wire saw through the gap of the support column to cut the column pier; after cutting, put a hoop with a matching size, which can be temporarily fixed in the reserved sections at the upper and lower ends of the column pier; 8) Select a liquid bag that matches the size of the column pier, place it in the cutting area of the column pier, and then connect the pressure gauge, the water supply and drainage valve and the pressure-maintaining water supply device; 9) Water filling and pressure testing: Install a displacement meter between the upper and lower column ends, and then fill the high-pressure liquid bag with water and pressurize it until there is a sign of upward movement at the upper column end, and then relieve the pressure; 10) Weighing and pressure measurement: Loosen the surrounding lifting support columns. If there is a sign of sinking of the upper column, pressurize the water supply of the liquid bag to push the upper column end back to the original elevation, and then this pressure is the target value for maintaining the water pressure, 11) Installation of casing: First, place the pre - installed collar around the casing unit along the column pier to be underpinned in a circle with adjacent ones. Then lower the placed collar. When encountering an obstacle at the rubber convex, increase the downward force of the collar. After the rubber convex deforms, the lower collar can pass through the rubber convex of this layer. In this way, there is a collar installed above each corresponding rubber convex; continue to squeeze the collar towards the rubber convex. When there is a feeling of tightening, stop squeezing the collar. 12) Re - tighten all the supports again, and the equipment is in the automatic standby state.

3. The construction method as described in claim 2, and it is characterized in that The method also includes the state adjustment of the lifting support columns: 1) In the case of settlement or suspension of work of the column to be underpinned, the standby state of the lifting support column is to tightly hold the upper and lower steel corbels. When the column settles and the water pressure measured by the pressure gauge decreases, the pressure - maintaining water supply device automatically adjusts the water supply to ensure that the upper column returns to the original elevation state. Then adjust the lifting support columns one by one to extend them to the tight - holding state. 2) In the case of settlement and uplift of the column to be underpinned, the standby state of the lifting support column is the unloaded state.

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