An active control device and method for controlling the deformation of adjacent buildings and structures in an excavation pit using a combination of recyclable and extendable sheet piles and formwork bags, and its application.

Abstract

This invention belongs to the field of protection of structures surrounding foundation pit excavation. It discloses an active control device and method for regulating the deformation of structures near foundation pits, which combines recyclable and extendable sheet piles and formwork bags, and its application. Before construction, a V-shaped composite cone and the front end of the sheet pile are assembled together. A foldable formwork bag is placed on the outside of the V-shaped composite cone, and the V-shaped area at the front end of the formwork bag is sealed, resulting in left and right formwork bags. A grouting hose passes through the grouting hole on the cone, connects the grouting port of the formwork bag to the cast iron continuous grouting pipe inside the cone, and a V-shaped thin-walled steel plate is set on the outside of the formwork bag, which is inserted into the stratum along with the sheet pile to protect the formwork bag. When the deformation of the structure exceeds the warning value, a slow-setting grout is injected into the formwork bag closer to the structure to regulate its deformation development. When the sheet pile is pulled out and recycled, the formwork bag away from the structure is activated to fill the gap and generate secondary stress compensation, thereby achieving active, responsive, and stable deformation control.

Description

Technical Field

[0001] This invention relates to the field of geotechnical engineering, specifically to an active control device and method for controlling the deformation of adjacent structures in foundation pits using a combination of recyclable and extendable sheet piles and formwork bags, belonging to the field of protection of structures surrounding foundation pit excavation. Background Technology

[0002] With the continuous development of urban underground space, new foundation pit projects and underground tunnel projects are often located adjacent to existing buildings and structures. During the unloading process of construction, the original stress balance of the soil strata is disrupted, which can easily lead to adverse effects such as displacement and deformation of surrounding buildings and structures. Therefore, in order to protect buildings and structures in a timely manner during construction and reduce construction risks, technicians and scholars have proposed various protective measures from three aspects: deformation source control, propagation path isolation, and active protection. According to different control concepts, these measures can be divided into passive control measures and active control measures. Traditional passive control measures mainly include increasing the stiffness of the support structure, soil reinforcement, setting up partition walls for zoned construction, and inserting isolation piles. Although these measures have been widely adopted and used, they generally suffer from problems such as "difficulty in predicting deformation, low control effect, and high construction cost." Moreover, they have not fundamentally reduced the stress loss of the strata caused by construction, and only control from the perspective of deformation, which has certain shortcomings.

[0003] For active deformation control, the main technologies include steel support axial force servo technology and grouting technology. Steel support axial force servo technology acquires deformation data through displacement sensors, and uses software to drive motors to adjust the support axial force, thereby controlling the deformation of the retaining structure. Examples include CN 223410175 U (a steel support servo support system for intelligent control of internal support axial force and deformation), CN212899239 U (steel support axial force servo system), and CN 212772378 U (a servo system for the support axial force of a foundation pit retaining structure). Although steel support axial force servo technology offers strong control and can precisely control soil deformation, its high cost and long construction time limit its application.

[0004] In recent years, some scholars have proposed the bladder grouting technology, such as CN 113638398 A (a method for active dynamic control of soil stress by bladder grouting) and CN 114136267 A (a dynamic control system for soil deformation based on composite bladders). The grouting pipe is placed inside the bladder, and the bladder is divided into sections by using binding straps and then grouting is performed to expand it.

[0005] Other scholars have proposed the technology of forming piles using geotextile bags, such as CN 207109807 U (a high-strength geotextile bag pile) and CN107130633 A (a construction method for a composite retaining structure of steel pipe concrete geotextile bag piles), which involves encasing the entire internal device inside the geotextile bag and then grouting it to form an integral concrete geotextile bag pile.

[0006] However, the implementation of the above technologies has the following obvious drawbacks:

[0007] 1. The grouting device can only be installed after drilling holes in the soil using a drilling rig, especially in the case of concrete formwork piles where the grouting device is relatively large, requiring even larger diameter holes. Drilling holes in the soil can lead to further loss of ground stress, resulting in secondary deformation of surrounding structures even before protection begins.

[0008] 2. Secondly, the above-mentioned support effect relies on inserting the grouting device into the mold bag, and then injecting grout from the inside to solidify and form an integral pile. The grouting device cannot be recovered afterward, which increases the support cost.

[0009] 3. Furthermore, the support piles used in the above technologies are not distributed in a surface manner, but rather in a point-centered support form, such as cylindrical piles. This results in the stress compensation effect being concentrated in a local area, providing only localized stress compensation. However, the area affected by stress loss on a building is relatively large, making it difficult to address the need for stress compensation over a large area, leading to unstable deformation control.

[0010] Therefore, there is currently a lack of building deformation control methods that can simultaneously solve the above-mentioned technical problems at low cost and high efficiency. Summary of the Invention

[0011] Therefore, this invention proposes an active method for controlling the deformation of adjacent structures in a foundation pit, employing recyclable, overlapping sheet piles and grouting the formwork bag from the outside. In the early stages of structure deformation, the sheet piles can be used to insert the formwork bag into the ground from the outside. When the deformation reaches a warning level, grouting is performed on one side of the formwork bag to generate surface stress compensation, thereby controlling the deterioration of deformation in surrounding structures. Simultaneously, after construction is completed and the deformation stabilizes, the sheet piles can be pulled out and recycled. The other side of the formwork bag can then undergo secondary grouting for stress compensation, promptly filling gaps and enhancing the control effect, preventing deformation control failure.

[0012] Specifically, before construction, all devices are assembled sequentially and inserted into the ground along with the sheet piles. The continuous cast iron grouting pipe extends to the ground surface as the sheet piles are inserted. When the excavation causes the deformation of the structure to exceed the warning value, a slow-setting grout is injected through the continuous cast iron grouting pipe and then through a grouting hose into a mold bag on one side of the V-shaped composite cone, causing it to expand and regulate the deformation. When the sheet piles are subsequently pulled out and recovered, secondary stress compensation can be performed by grouting the other mold bag. Therefore, this invention has the advantages of simple construction, excellent control effect, high economic benefits, and strong applicability.

[0013] The objective of this invention is achieved through the following technical solutions:

[0014] An active deformation control device for adjacent structures in an excavation pit, comprising a combination of recyclable and extendable sheet piles and formwork bags, including:

[0015] The V-shaped composite cone has its tip pointing downwards, and its upper surface is provided with a groove of a certain depth that allows sheet piles to be inserted or pulled out from above; grouting holes are pre-drilled on the outer surfaces of the left and right sides of the V-shaped surface of the V-shaped composite cone.

[0016] Sheet piles are composed of steel sheets. The lower edge of each sheet pile can be inserted into the groove of the V-shaped composite cone, so that when pressure is applied to the sheet pile from above, the V-shaped composite cone can be inserted into the soil. The two sides of the sheet pile are lap joints, allowing multiple sheet piles to be spliced ​​and extended in the horizontal direction, thereby cooperating with multiple V-shaped composite cones and foldable mold bags to achieve surface stress compensation.

[0017] The foldable molded bag, after being folded, fits against the outer side of the V-shaped surface of the V-shaped composite cone. The contact surface between the foldable molded bag and the V-shaped composite cone is provided with multiple grouting ports, and each grouting port is connected to a grouting hole of the V-shaped composite cone.

[0018] The grouting hose passes through the grouting hole and connects the grouting port of the foldable mold bag to the cast iron continuous grouting pipe inside the V-shaped surface of the V-shaped composite cone; the number of the grouting hose and the cast iron continuous grouting pipe corresponds to the number of the corresponding grouting ports.

[0019] A continuous cast iron grouting pipe is located inside the V-shaped surface of a V-shaped composite cone. As the V-shaped composite cone enters the soil, the continuous cast iron grouting pipe can overlap and extend its length to the ground surface to facilitate grouting of the manhole bag deep in the soil from the ground.

[0020] A V-shaped thin-walled steel plate covers the V-shaped composite cone and the mold bag below, thereby protecting the front mold bag in the forward direction; the V-shaped thin-walled steel plate is provided with a corresponding protruding channel from the height of each grouting port to the top of the V-shaped thin-walled steel plate to allow the grout injected from the grouting port to flow into the upper mold bag.

[0021] Preferably, the area where the mold bag contacts the top of the V-shaped composite cone is pre-sealed, and the mold bags on the left and right sides are used for grouting respectively.

[0022] Preferably, the overlapping joints on both sides of the sheet pile are S-shaped; the groove of the V-shaped composite cone head connects to the lower end of the unbent middle part of the sheet pile.

[0023] Preferably, the lengths of the molded bags located on both sides of the V-shaped surface are equal.

[0024] Preferably, the V-shaped composite cone is equipped with a steel support to prevent excessive soil pressure from damaging the V-shaped composite cone when it is inserted into the stratum.

[0025] This invention also provides a method for actively regulating the deformation control of structures adjacent to a foundation pit using the aforementioned deformation control device, characterized by comprising the following steps:

[0026] Step 1: Before construction, assemble the V-shaped composite cone head and the sheet pile together.

[0027] Step 2: Place the foldable mold bag on the outside of the V-shaped composite cone and align the grouting port on the mold bag with the pre-drilled grouting hole on the cone.

[0028] Step 3: Connect the grouting hose to the pre-drilled grouting hole on the V-shaped composite cone head, and connect the outer mold bag and the inner cast iron continuous grouting pipe of the V-shaped composite cone head. Set a V-shaped thin-walled steel plate on the outside of the mold bag to protect the mold bag from wear when the device is inserted into the formation.

[0029] Step 4: As the sheet piles are gradually inserted, the cast iron continuous grouting pipe inside the V-shaped composite cone head is continuously overlapped and extended.

[0030] Step 5: When the excavation of the foundation pit causes the deformation of the building structure to exceed the warning value, the formwork bag closer to the building structure is activated first. That is, slow-setting grout is injected into the cast iron continuous grouting pipe closer to the building structure and flows through the grouting hose to the formwork bag on the outside of the V-shaped composite cone. During grouting, the steel sheet pile can provide expansion reaction force. During the grouting process, because the soil pressure at deep depth is greater than the soil pressure at shallow depth, under the combined action of expansion reaction force and the difference in soil pressure, the grout will flow to the upper part of the formwork bag and gradually and evenly expand the entire formwork bag, thereby providing stress compensation for the soil near the building structure and inhibiting the development of building structure deformation.

[0031] Step 6: After the grout in one side of the formwork bag has solidified and the deformation control effect has stabilized, as the sheet piles are gradually pulled out and recovered, grout is injected into the formwork bag on the side away from the building structure. This causes the grout to expand and fill the gaps created by pulling out the sheet piles, thus performing secondary stress compensation and reducing the stress loss in the stratum caused by pulling out the sheet piles. This works together with the first side formwork bag to regulate soil deformation.

[0032] Preferably, in step 1, the number of grouting holes on both sides of the V-shaped composite cone is 2-5.

[0033] Preferably, in step 2, the foldable formwork bag is made of high-strength, tear-resistant, and foldable material. Its length and width can be customized according to the insertion depth of the stratum and the size of the sheet pile. The V-shaped area at the front end of the foldable formwork bag is pre-sealed, and the left and right sides of the formwork bag are grouted and expanded separately. This can also prevent the formwork bag from being damaged by pressure due to mutual compression during subsequent grouting expansion.

[0034] The present invention also provides the application of the above-mentioned deformation control device or deformation control method in the control of deformation of structures near the foundation pit.

[0035] The present invention has the following technical effects:

[0036] 1. This invention folds the molding bag and distributes it from the outside on both sides of the V-shaped composite cone. At the same time, the steel sheet pile and the V-shaped cone can be detachably inserted. The molding bag is brought into the formation along with the steel sheet pile through the cone, so that the steel sheet pile can be recovered even after grouting, saving economic costs.

[0037] 2. The grouting control unit of this invention can be horizontally spliced ​​with steel sheet piles within the stratum to form a wall-like structure, thereby achieving stress compensation in the surface area and actively controlling deformation. Its support effect is superior to that of existing point-distributed formwork piles. The length and width of the formwork bag of this invention can be customized according to the insertion depth into the stratum and the size of the steel sheet piles, adapting to deformation control requirements under various conditions.

[0038] 3. During the grouting process, the steel sheet pile of the present invention will exert a reaction force to support the formwork bag on the grouting side, so that it can transfer the support force to the soil that needs stress compensation, and increase the expansion force of the grouting bag, thereby enhancing the deformation control effect.

[0039] 4. In this invention, the area in contact between the formwork bag and the top of the V-shaped composite cone is pre-sealed, and the left and right formwork bags are divided to enable grouting. In conjunction with the recycling of the steel sheet pile, the other formwork bag can achieve secondary stress compensation.

[0040] 5. To address the issue that the recovery of sheet piles can easily lead to stress loss in the stratum, resulting in a decrease in deformation control, the use of grouting expansion in the other side of the formwork bag can promptly fill the voids and perform secondary stress compensation, thereby improving the deformation control effect and stability.

[0041] 6. The grouting channel of the present invention consists of a grouting hose and a cast iron continuous grouting pipe. The grouting hose can flexibly connect the outer mold bag of the V-shaped composite cone head and the inner cast iron continuous grouting pipe. The inner cast iron continuous grouting pipe is threaded and can gradually overlap and extend to the ground surface as the steel sheet pile is inserted.

[0042] 7. The grouting port of each side of the formwork bag is located on the lower side of the soil. Since the soil pressure on the lower side of the soil is greater than that on the upper side, under the action of the soil pressure difference between the upper and lower soil layers, the grout will gradually flow to the upper part of the formwork bag after being injected from the grouting port. This prevents a large amount of grout from accumulating at the lower part of the formwork bag in the early stage of grouting. At the same time, under the combined action of the expansion reaction force of the steel sheet pile, uniform expansion is achieved after grouting, which plays a stable deformation control role.

[0043] 8. When the formwork bag is inserted into the soil, the V-shape can reduce the resistance of the hard soil and rock layers during the insertion process. At the same time, the V-shaped thin-walled steel plate covers the outside of the top of the formwork bag, which can protect the formwork bag from high-pressure tearing damage during the insertion of the sheet pile.

[0044] Compared with existing control technologies, concrete formwork piles have the advantages of flexibility, controllability, convenient construction, recyclability, and low cost. They also overcome the shortcomings of existing grouting technologies, such as stress loss in the strata, unstable control effect, and insignificant control strength caused by drilling and grouting. This invention achieves active control based on surface region stress compensation, which can effectively control the deformation of buildings and structures near the foundation pit and achieve active protection of buildings and structures. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of the active deformation control device for the combination of sheet piles and formwork bags.

[0046] Figure 2 This is a side view schematic diagram of an active deformation control device combining sheet piles and formwork bags.

[0047] Figure 3 This is a schematic diagram of a foldable molded bag.

[0048] Figure 4 This is a schematic diagram of inserting a V-shaped composite cone into a steel sheet pile.

[0049] Figure 5 A schematic diagram of the outer side of a V-shaped composite cone head fitted with a foldable molded bag.

[0050] Figure 6 A schematic diagram showing the connection between the foldable mold bag and the continuous cast iron grouting pipe for the grouting hose.

[0051] Figure 7 A schematic diagram of a foldable molded bag being fitted with a V-shaped thin-walled steel plate.

[0052] Figure 8 A cross-sectional view showing the insertion of the deformation control device between the foundation pit and the surrounding buildings.

[0053] Figure 9 Plan view showing the insertion of the deformation control device between the foundation pit and surrounding buildings.

[0054] Figure 10 This is a schematic diagram of the grouting expansion of the formwork bag near the building side in Example 2.

[0055] Figure 11 This is a schematic diagram of the grouting expansion of the formwork bag on the side away from the building in Example 2.

[0056] Figure 12 This is a plan view of the grouting expansion of the left and right mold bags in Example 2.

[0057] Figure 13Insert the deformation control device into the cross-sectional view between the proposed tunnel and the existing tunnel.

[0058] Figure 14 Insert the deformation control device into the plan view between the proposed tunnel and the existing tunnel.

[0059] Figure 15 This is a schematic diagram of the grouting expansion of the formwork bag on the side near the existing tunnel in Example 3.

[0060] Figure 16 This is a schematic diagram of the grouting expansion of the formwork bag on the side away from the existing tunnel in Example 3.

[0061] Figure 17 This is a plan view of the grouting expansion of the left and right mold bags in Example 3.

[0062] The reference numerals in the diagram are as follows: 1-Ground surface; 2-Building; 3-Foundation pit; 4-Diaphragm wall; 5-Foldable formwork bag; 6-V-shaped thin-walled steel plate; 7-Steel sheet pile; 8-Support; 9-Proposed tunnel; 10-Existing tunnel; 101-V-shaped composite cone; 102-Groove; 103-Grouting hole; 104-Steel support; 105-Grouting hose; 106-Cast iron continuous grouting pipe; 107-Protruding channel; 108-Grouting port. Detailed Implementation

[0063] The specific embodiments of the present invention will be described in detail below. In the description of the present invention, it should be noted that the terms "left side," "right side," "upper part," "lower part," "inner side," and "outer side," etc., indicating directions or relative positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and the context. The planar and cross-sectional schematic diagrams from different perspectives are only for the convenience of describing the implementation, operation, and structural relationships of the present invention, and therefore should not be construed as limiting the present invention.

[0064] Example 1

[0065] This invention discloses an active deformation control device for adjacent buildings and structures in an excavation pit, combining recyclable and extendable sheet piles and formwork bags. Figure 1 , Figure 2 , Figure 3 , Figure 4As shown, the main components include a V-shaped composite cone 101, sheet piles 7, grouting hoses 105, cast iron continuous grouting pipes 106, foldable molded bags 5, and V-shaped thin-walled steel plates 6. The V-shaped composite cone 101 has a downward-facing, rounded tip and six internal steel supports 104. The upper surface of the V-shaped composite cone 101 has a groove 102 with a depth of 210mm, allowing the sheet piles 7 to be inserted or removed from above. Two grouting holes 103 with a diameter of 32mm are pre-drilled on the outer surfaces of the left and right sides of the V-shaped surface of the V-shaped composite cone. The overlapping joints on both sides of the sheet piles 7 are S-shaped. The groove 102 of the V-shaped composite cone connects to the lower end of the unbent middle section of the sheet pile 7. The number of grouting hoses 105 and cast iron continuous grouting pipes 106 corresponds to the number of corresponding grouting ports 108; the diameter of the grouting hoses 105 and cast iron continuous grouting pipes 106 is 32mm. The foldable mold bag 5 has four grouting ports 108 that connect with the grouting holes 103 of the V-shaped composite cone head 101. The lengths of the mold bag on both sides of the V-shaped surface of the V-shaped composite cone head 101 are equal, and the area where the mold bag contacts the top of the V-shaped composite cone head 101 is pre-sealed. The V-shaped thin-walled steel plate 6 has four corresponding protruding channels 107 from the height of each grouting port 108 to the top of the V-shaped thin-walled steel plate 6.

[0066] Example 2

[0067] This invention provides a case study on the protection of a building adjacent to a foundation pit. The foundation pit 3 has an excavation depth of 16m and is being excavated in four layers. An existing building 2 exists nearby, spaced 10m apart, with building 2 measuring 20m x 10m. As excavation progresses, building 2 will experience cracking and deformation due to the excavation of foundation pit 3. In this embodiment, before construction, steel sheet piles 7 are inserted between foundation pit 3 and building 2, thereby bringing the entire combined active deformation control device into the ground at an insertion depth of 14m. The foldable formwork 5 contains a closed area 29m long and 0.5m wide, thereby providing regional stress compensation to protect the adjacent building 2. To implement this case, the following implementation steps further illustrate the characteristics, functions, and usage of this invention:

[0068] Step 1: Before constructing foundation pit 3, assemble the V-shaped composite cone head 101 and the sheet pile 7 together, as follows: Figure 4 As shown, the outer surfaces of the left and right sides of the V-shaped composite cone 101 each have two grouting holes 103 with a diameter of 32mm, and the V-shaped composite cone 101 has 6 steel supports 104 inside.

[0069] Step 2, attach the foldable molded bag 5 to the outside of the V-shaped composite cone head 101, and make... Figure 3 The grouting port 108 on the mold bag shown is aligned with the pre-drilled grouting hole 103 on the V-shaped composite cone head 101, and the grouting hole 103 is as follows: Figure 5 As shown;

[0070] Step 3, connect the grouting hose 105. Figure 4 The pre-drilled grouting hole 103 on the V-shaped composite cone 101 shown connects the outer mold bag of the V-shaped composite cone 101 and the inner cast iron continuous grouting pipe 106. The cast iron continuous grouting pipe 106 is as follows: Figure 6 As shown. A V-shaped thin-walled steel plate 6 is installed on the outside of the mold bag to protect it from wear when the device is inserted into the formation. The V-shaped thin-walled steel plate 6 has four corresponding... Figure 3 The grouting port 108 shown has an outwardly protruding channel 107, which is as follows: Figure 7 As shown;

[0071] Step 4: Using a pile driver, steel sheet piles 7 are gradually inserted between the diaphragm wall 4 and the building 2, continuously overlapping and extending the cast iron continuous grouting pipe 106 inside the V-shaped composite cone head 101, as shown. Figure 8 The cross-sectional view is shown. Sheet piles 7 are spliced ​​and extended horizontally along the stratum plane, in conjunction with multiple... Figure 7 The V-shaped composite cone 101 and the foldable mold bag 5 shown, and the spliced ​​and extended steel sheet pile 7 are as follows: Figure 9 As shown in the plan view. To ensure the control effect, the horizontal splicing extension length of the sheet pile 7 should be greater than the length of the building 2 by no less than 1m. At the same time, a length of more than 0.5m of the sheet pile 7 and the cast iron continuous grouting pipe 106 should be reserved to the ground surface 1 so that the sheet pile 7 can be pulled out and recovered later and grouting can be performed on the ground through the cast iron continuous grouting pipe 106.

[0072] Step 5: When the third layer of soil in foundation pit 3 is excavated to a depth of 11m, causing the deformation of building 2 to exceed the warning value, the formwork bag closer to the side of building 2 is activated. This involves injecting retarded grout into the continuous cast iron grouting pipe 106 on the side closer to building 2. Figure 6 The grouting hose 105 shown flows towards the formwork bag closer to the building side outside the V-shaped composite cone head 101, expanding to a designed diameter of 50mm. After expansion, the formwork bag closer to the building side... Figure 10 As shown. During grouting, the sheet pile 7 can provide expansion reaction force. During the grouting process, since the soil pressure at the deep end is greater than that at the shallow end, under the combined action of the expansion reaction force and the difference in soil pressure, the grout will flow to the upper part of the formwork bag and gradually and evenly expand the entire formwork bag, thereby providing stress compensation for the soil near the building 2 and inhibiting the deformation development of the building 2.

[0073] Step 6: After the grout in the formwork bag closer to building 2 has solidified and the deformation control effect has stabilized, gradually pull out and recover the sheet pile 7. Then, inject grout into the formwork bag on the side farther from building 2, causing it to expand to the designed diameter of 70mm. Figure 11 As shown in the cross-sectional view, this process fills the voids created by the extraction of sheet pile 7, performs secondary stress compensation, reduces the stress loss in the soil caused by the extraction of sheet pile 7, and works together with the first side formwork to regulate soil deformation. Figure 12 As shown in the plan view. The above steps achieve the protection of buildings adjacent to the foundation pit.

[0074] Example 3

[0075] This invention provides a protection project for an existing tunnel adjacent to a proposed tunnel, with a distance of 20m between the two tunnels and a diameter of 8m. A soft soil area exists between the proposed tunnel 9 and the existing tunnel 10. As construction of the proposed tunnel 9 progresses, the existing tunnel 10 gradually shifts and deforms towards the proposed tunnel 9. In this case, before the proposed tunnel 9 is excavated to the soft soil area, sheet piles 7 are inserted between the proposed tunnel 9 and the existing tunnel 10, thereby bringing the entire combined active deformation control device to the stratum. The insertion depth is 12.5m, and the entire formwork bag contains a closed area 26m long and 0.6m wide, thereby providing regional stress compensation protection for the existing tunnel 10. To implement this case, the following implementation steps further illustrate the characteristics, functions, and usage of this invention:

[0076] Step 1: Before excavating the proposed tunnel 9 to the soft soil area, the V-shaped composite cone head 101 and the steel sheet pile 7 are fitted and assembled together, as shown below. Figure 4 As shown;

[0077] Step 2, attach the foldable molded bag 5 to the outside of the V-shaped composite cone head 101, and make... Figure 3 The grouting port 108 on the mold bag shown is aligned with the pre-drilled grouting hole 103 on the V-shaped composite cone head 101, and the grouting hole 103 is as follows: Figure 5 As shown;

[0078] Step 3, connect the grouting hose 105. Figure 4 The pre-drilled grouting hole 103 on the V-shaped composite cone 101 shown connects the outer mold bag of the V-shaped composite cone 101 and the inner cast iron continuous grouting pipe 106. The cast iron continuous grouting pipe 106 is as follows: Figure 6 As shown. A V-shaped thin-walled steel plate 6 is installed on the outside of the molded bag, as shown. Figure 7 As shown;

[0079] Step 4: Using a pile driver, steel sheet piles 7 are gradually inserted between the proposed tunnel 9 and the existing tunnel 10, continuously overlapping and extending the cast iron continuous grouting pipe 106 inside the V-shaped composite cone head 101, as shown below. Figure 13 The cross-sectional view is shown. Sheet piles 7 are spliced ​​and extended horizontally along the stratum plane, in conjunction with multiple... Figure 7 The V-shaped composite cone 101 and the foldable mold bag 5 shown, and the spliced ​​and extended steel sheet pile 7 are as follows: Figure 14As shown in the plan view. To ensure the control effect, the horizontal splicing extension length of the sheet pile 7 should be at least 2m longer than the soft soil area. At the same time, a length of more than 0.5m of sheet pile 7 and a continuous cast iron grouting pipe 106 should be reserved to the ground surface 1 for subsequent extraction and recovery of sheet pile 7 and grouting.

[0080] Step 5: When the deformation of the existing tunnel 10, which is located in the soft soil layer during the construction of the proposed tunnel 9, exceeds the warning value, the formwork bag closer to the existing tunnel 10 is activated. This involves injecting retarded grout into the cast iron continuous grouting pipe 106 closer to the existing tunnel 10. Figure 6 The grouting hose 105 shown flows to the formwork bag on the side of the V-shaped composite cone 101 closest to the existing tunnel 10, expanding to a designed diameter of 40mm. After expansion, the formwork bag on the side closest to the existing tunnel 10 is as follows: Figure 15 As shown. During grouting, the sheet pile 7 can provide expansion reaction force. During the grouting process, since the soil pressure at the deep end is greater than that at the shallow end, under the combined action of the expansion reaction force and the difference in soil pressure, the grout will flow to the upper part of the formwork bag and gradually and evenly expand the entire formwork bag, thereby providing stress compensation for the soil near the existing tunnel 10 and inhibiting the deformation development of the existing tunnel 10.

[0081] Step 6: After the grout solidification and deformation control effect in the formwork bag closer to the existing tunnel 10 has stabilized, and the sheet piles 7 are gradually pulled out and recovered, grout is injected into the formwork bag on the side farther from the existing tunnel 10, causing it to expand to the designed diameter of 50mm. Figure 16 As shown in the cross-sectional view, this process fills the voids created by the extraction of sheet pile 7, performs secondary stress compensation, reduces the stress loss in the soil caused by the extraction of sheet pile 7, and works together with the first side formwork to regulate soil deformation. Figure 17 As shown in the plan view. The above steps achieve the protection of the existing tunnel.

[0082] The above description is only a few embodiments of the present invention and is not intended to limit the implementation and protection scope of the present invention. For those skilled in the art, any solutions obtained by making equivalent conversions or obvious changes based on the content of the present invention specification and drawings shall fall within the protection scope of the present invention.

Claims

1. A device for actively controlling the deformation of adjacent structures in an excavation pit using a combination of recyclable and extendable sheet piles and formwork bags, characterized in that, include: V-shaped composite cone (101), the tip of the V-shaped composite cone (101) is facing downward, the upper surface of the V-shaped composite cone (101) is provided with a groove (102) of a certain depth that allows the steel sheet pile (7) to be inserted or pulled out from above; the outer surfaces of the left and right sides of the V-shaped surface of the V-shaped composite cone (101) are pre-drilled with grouting holes (103). Sheet piles (7) are made of steel plates. The lower edge of each sheet pile (7) can be inserted into the groove (102) of the V-shaped composite cone (101), so that when pressure is applied to the sheet pile (7) from above, the V-shaped composite cone (101) can be inserted into the soil. The two sides of the sheet pile (7) are overlapping joints, allowing multiple sheet piles (7) to be spliced ​​and extended in the horizontal direction, thereby cooperating with multiple V-shaped composite cones (101) and foldable mold bags (5) to achieve surface stress compensation. The foldable mold bag (5) is folded and attached to the outside of the V-shaped surface of the V-shaped composite cone (101). The foldable mold bag (5) and the V-shaped composite cone (101) are provided with multiple grouting ports (108). Each grouting port (108) is connected to a grouting hole (103) of the V-shaped composite cone (101). Grouting hose (105), which passes through grouting hole (103) and connects grouting port (108) of foldable mold bag (5) to cast iron continuous grouting pipe (106) on the inner side of V-shaped surface of V-shaped composite cone (101); the number of grouting hose (105), cast iron continuous grouting pipe (106) and corresponding grouting port (108) corresponds to the number of grouting hose (105) and cast iron continuous grouting pipe (106); A continuous cast iron grouting pipe (106) is located inside the V-shaped surface of a V-shaped composite cone (101). As the V-shaped composite cone (101) enters the soil, the continuous cast iron grouting pipe (106) can overlap and extend its length to the ground surface to facilitate grouting of the manhole bag deep in the soil from the ground. A V-shaped thin-walled steel plate (6) covers the V-shaped composite cone (101) and the foldable mold bag (5) to protect the front mold bag in the forward direction; the V-shaped thin-walled steel plate (6) has a corresponding protruding channel (107) at the height of each grouting port (108) to the top of the V-shaped thin-walled steel plate (6) to allow the grout injected by the grouting port (108) to flow into the upper mold bag; The area where the foldable mold bag (5) contacts the top of the V-shaped composite cone (101) is pre-sealed, and the left and right mold bags are divided to enable grouting respectively.

2. The deformation control device according to claim 1, characterized in that, The two sides of the sheet pile (7) have an S-shaped joint; the groove (102) of the V-shaped composite cone (101) connects to the lower end of the unbent part in the middle of the sheet pile (7).

3. The deformation control device according to claim 1, characterized in that, The molded bags on both sides of the V-shaped surface are of equal length.

4. The deformation control device according to claim 1, characterized in that, The V-shaped composite cone (101) is equipped with a steel support (104) to prevent the V-shaped composite cone (101) from being damaged by excessive soil pressure when inserted into the stratum.

5. A method for actively regulating the deformation control of structures adjacent to an excavation pit using the deformation control device according to any one of claims 1-4, characterized in that, Includes the following steps: Step 1: Before construction, assemble the V-shaped composite cone (101) and the sheet pile (7) together. Step 2: Place the foldable mold bag (5) on the outside of the V-shaped composite cone (101) and align the grouting port (108) on the foldable mold bag (5) with the pre-opened grouting hole (103) on the V-shaped composite cone (101). Step 3: Connect the grouting hose (105) through the pre-drilled grouting hole (103) on the V-shaped composite cone (101) to the foldable mold bag (5) on the outside of the V-shaped composite cone (101) and the cast iron continuous grouting pipe (106) on the inside, and set a V-shaped thin-walled steel plate (6) on the outside of the mold bag, so as to protect the mold bag from wear when the device is inserted into the formation; Step 4: As the sheet pile (7) is gradually inserted, the inner side of the cast iron continuous grouting pipe (106) of the V-shaped composite cone (101) is continuously overlapped and extended. Step 5: When the excavation of the foundation pit (3) causes the deformation of the building to exceed the warning value, the formwork bag closer to the building is activated first. That is, the slow-setting grout is injected into the cast iron continuous grouting pipe (106) closer to the building and flows through the grouting hose (105) to the formwork bag on the outside of the V-shaped composite cone (101). During grouting, the steel sheet pile (7) can provide expansion reaction force. During the grouting process, since the soil pressure at the deep end is greater than the soil pressure at the shallow end, under the combined action of the expansion reaction force and the difference in soil pressure of the stratum, the grout will flow to the upper part of the formwork bag and gradually expand the entire formwork bag evenly, thereby providing stress compensation for the soil near the building and suppressing the deformation development of the building. Step 6: After the grout in the mold bag on one side has solidified and the deformation control effect has stabilized, the steel sheet pile (7) is gradually pulled out and recycled. Grout is injected into the mold bag on the side away from the building structure to expand and fill the gap generated by pulling out the steel sheet pile (7), so as to perform secondary stress compensation, reduce the stress loss of the stratum caused by pulling out the steel sheet pile (7), and work together with the first mold bag to regulate the deformation of the soil.

6. The deformation control method according to claim 5, characterized in that, In step 1, the number of grouting holes (103) on both sides of the V-shaped composite cone (101) is 2-5.

7. The deformation control method according to claim 5, characterized in that, In step 2, the foldable mold bag (5) is made of high-strength, tear-resistant, and foldable material. Its length and width can be customized according to the depth of insertion into the stratum and the size of the sheet pile (7). The V-shaped area at the front end of the foldable mold bag (5) is pre-sealed and divided into left and right mold bags for grouting and expansion. This also avoids the mold bag from being damaged by pressure due to mutual compression during subsequent grouting expansion.

8. The application of the deformation control device according to any one of claims 1-4 or the deformation control method according to any one of claims 6-7 in controlling the deformation of structures adjacent to the foundation pit.

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