Supporting mechanism for foundation pit excavation

Abstract

The invention relates to the technical field of constructional engineering, in particular to a supporting mechanism for foundation pit excavation, which comprises two rows of supporting walls, each row of supporting walls comprises a plurality of Larsen steel sheet piles, the relatively convex part of the inner side of each supporting wall is used as a first pressing part, and the outer side of each supporting wall is used as a second pressing part. A relatively concave part on the inner side of the supporting wall body is used as a second pressing part; pressure-bearing seats are arranged on the inner sides of the two rows of supporting wall bodies, each pressure-bearing seat is provided with a plurality of supporting rods, and the supporting rods can slide in the direction perpendicular to the wall surfaces of the supporting wall bodies so as to be supported on the first abutting parts or the second abutting parts; all Larsen steel sheet piles can be supported by means of supporting of the supporting rods, the rigidity of the Larsen steel sheet piles and the parts inserted into soil at the same time, and the reliability during supporting can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of construction engineering, and in particular to a supporting mechanism used for foundation pit excavation. Background Art

[0002] Foundation pit support is an important technology in construction engineering, which aims to support, reinforce and protect the soil around the foundation pit through various support structures to ensure its stability and safety.

[0003] When selecting a foundation pit support structure, it is necessary to comprehensively consider multiple factors such as geological conditions, surrounding environment, and construction technology; common foundation pit support structures include soil nail walls, pile support, anchor cable support, and Larsen steel sheet pile support; among them, Larsen steel sheet piles are also called U-shaped steel sheet piles. When the Larsen steel sheet piles are in use, the edge of the foundation pit is first supported by the Larsen steel plate, and then the Larsen steel plates on both sides are supported from the inside by supporting steel. Due to processing errors in the Larsen steel plate and installation errors during the construction process, there are many inconveniences in installing the Larsen steel sheet piles.

[0004] To solve the above problems, related technologies, such as Chinese patent CN114622576B, disclose a support device with an anti-collapse structure for trench excavation. When in use, the support device with an anti-collapse structure for trench excavation realizes that the hydraulic drive component is connected to the anti-collapse pressure component through a hydraulic pipe with a joint based on the hydraulic principle, and then controls the active end of the anti-collapse pressure component to perform axial displacement, so that the pressure-bearing component abuts against the inner side of the support wall, thereby realizing an adjustable support length and achieving reliable support for the support wall.

[0005] Although the above-mentioned support device with an anti-collapse structure for trench excavation has the function of adjusting the support length, it is found in actual use that the pressure-bearing component is mainly supported on the inwardly convex Larsen steel plate, and the hook end of the inwardly convex Larsen steel plate is set inwardly, and the hook end of the outwardly convex Larsen steel plate is set outwardly. Under the push of the pressure-bearing component, the hook end of the inwardly convex Larsen steel plate will be separated from the hook end of the outwardly convex Larsen steel plate, resulting in the outwardly convex Larsen steel plate still mainly relying on its own rigidity and the part inserted into the soil for support, thereby affecting the reliability of the support. Summary of the invention

[0006] Based on this, it is necessary to provide a supporting mechanism for foundation pit excavation to address the problem of poor support reliability in the current foundation pit support process.

[0007] The above purpose is achieved through the following technical solutions: A supporting mechanism for foundation pit excavation, the supporting mechanism for foundation pit excavation comprising a supporting wall, the supporting wall having two rows, each row of the supporting wall comprising a plurality of Larsen steel sheet piles, a relatively convex portion on the inner side of the supporting wall serving as a first pressure portion, and a relatively concave portion on the inner side of the supporting wall serving as a second pressure portion; pressure seats are provided on the inner sides of the two rows of supporting walls, each of the pressure seats is provided with a plurality of support rods, the support rods being able to slide in a direction perpendicular to the wall surface of the supporting wall to be supported on the first pressure portion or the second pressure portion.

[0008] Further, the supporting force generated by the supporting rod supported on the first pressing portion is F1, and the supporting force generated by the supporting rod supported on the second pressing portion is F2, and F1<F2.

[0009] Furthermore, the supporting mechanism for foundation pit excavation also includes a hydraulic drive assembly, and the hydraulic drive assembly is configured to provide a driving force for the sliding of the support rod.

[0010] Furthermore, the hydraulic drive assembly includes a plurality of hydraulic cylinder bodies, the hydraulic cylinder bodies are inserted into the pressure-bearing seat and are configured to receive hydraulic fluid from the outside; the support rods are inserted into the hydraulic cylinder bodies.

[0011] Furthermore, the supporting mechanism for foundation pit excavation also includes a cut-off component, which is configured to cut off the hydraulic pressure of the hydraulic fluid on the support rod when the support rod moves outward by a distance greater than or equal to a preset distance.

[0012] Furthermore, the cut-off assembly includes two cut-off pieces, which are inserted into the hydraulic cylinder body and are respectively located on both sides of the liquid flow channel in the hydraulic cylinder body. The cut-off pieces can elastically slide in a direction perpendicular to the liquid flow channel, and have corresponding first positions and second positions before and after sliding. When in the first position, the two cut-off pieces simultaneously stop on both sides of the support rod; when in the second position, the two cut-off pieces are sealed and abutted.

[0013] Furthermore, the abutting surfaces of the two truncated pieces are keyed together.

[0014] Furthermore, all the hydraulic cylinder bodies in the same group are interconnected.

[0015] Furthermore, the support mechanism for foundation pit excavation also includes a hydraulic drive component, which is configured to provide a driving force for the two pressure-bearing seats to move synchronously in directions away from or towards each other, so as to adapt to the two rows of support walls with different spacings.

[0016] Furthermore, the hydraulic drive component is a manual hydraulic bidirectional drive cylinder or an electric bidirectional hydraulic drive cylinder.

[0017] The beneficial effects of the present invention are: When the supporting mechanism for foundation pit excavation involved in the present invention is used, the edge of the foundation pit is first supported by two rows of supporting walls, and then two pressure-bearing seats are respectively placed on the inner sides of the two rows of supporting walls, and then the supporting rods are driven to slide along the wall direction perpendicular to the supporting wall and in the direction close to the supporting wall to support on the first pressing part or the second pressing part, so that all Larsen steel sheet piles can simultaneously support the foundation pit by relying on the support of the supporting rods, their own rigidity and the parts inserted into the soil, thereby facilitating improving the reliability of support.

[0018] Furthermore, by arranging that the supporting force generated by the supporting rod supported on the first pressing part is smaller than the supporting force generated by the supporting rod supported on the second pressing part, when in use, the Larsen steel sheet piles corresponding to the second pressing part have a tendency to move outward relative to the Larsen steel sheet piles corresponding to the first pressing part, thereby making the hook ends of the two adjacent Larsen steel sheet piles tend to be pressed tightly, which is beneficial to improving the sealing performance while improving the connection stability between the two adjacent Larsen steel sheet piles, thereby reducing the amount of external water and soil that penetrates into the foundation pit through the gap between the two adjacent Larsen steel sheet piles.

[0019] Furthermore, by setting up a cut-off component, during use, when the support rod moves outward a distance greater than or equal to a preset distance, the cut-off component cuts off the hydraulic pressure of the hydraulic fluid on the support rod, so that the support rod no longer supports the corresponding Larsen steel sheet pile, thereby avoiding damage to the Larsen steel sheet pile. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of the three-dimensional structure of a supporting mechanism for foundation pit excavation provided by an embodiment of the present invention when supporting a foundation pit; Figure 2 for Figure 1 A schematic diagram of the partially enlarged structure at center A; Figure 3 A schematic diagram of the three-dimensional structure of a support mechanism for foundation pit excavation provided by an embodiment of the present invention; Figure 4 A schematic diagram of the three-dimensional structure of the pressure bearing seat, support rod, connecting pipe, hydraulic cylinder body and cut-off assembly of the support mechanism for foundation pit excavation provided by the embodiment of the present invention when assembled; Figure 5 A schematic diagram of a three-dimensional cross-sectional structure of a pressure bearing seat, a support rod, a connecting pipe, a hydraulic cylinder body and a cut-off assembly of a support mechanism for foundation pit excavation provided by an embodiment of the present invention during assembly; Figure 6 for Figure 5A schematic diagram of the partially enlarged structure at B in the middle; Figure 7 for Figure 5 Schematic diagram of the partial enlarged structure at point C in the middle.

[0021] in: 1. Support wall; 11. Larsen steel sheet pile; 12. First pressing part; 13. Second pressing part; 2. Pressure bearing seat; 21. Support rod; 22. Connecting pipe; 3. Hydraulic cylinder body; 301. Connecting channel; 4. Cut-off assembly; 41. Cut-off piece; 42. Compression spring; 5. Electric bidirectional hydraulic drive cylinder. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below through embodiments and in conjunction with the accompanying drawings. 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.

[0023] The serial numbers assigned to the components herein, such as "first", "second", etc., are only used to distinguish the objects described and do not have any order or technical meaning. The "connection" and "coupling" mentioned herein, unless otherwise specified, include direct and indirect connections (couplings). In the description of the present invention, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc., indicating the orientation or position relationship are 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, rather than indicating or implying 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 to the present invention.

[0024] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0025] like Figures 1 to 7As shown, the supporting mechanism for foundation pit excavation provided by the embodiment of the present invention is arranged to include a supporting wall 1, and the supporting wall 1 has two rows, and each row of the supporting wall 1 includes a plurality of Larsen steel sheet piles 11, and the relatively convex portion on the inner side of the supporting wall 1 serves as a first pressing portion 12, and the relatively concave portion on the inner side of the supporting wall 1 serves as a second pressing portion 13; pressure-bearing seats 2 are arranged on the inner sides of the two rows of supporting walls 1, and a plurality of support rods 21 are arranged on each pressure-bearing seat 2, and the support rods 21 can slide in a direction perpendicular to the wall surface of the supporting wall 1 to be supported on the first pressing portion 12 or the second pressing portion 13.

[0026] Specifically in this embodiment, Figure 1 As shown, the two rows of supporting walls 1 are respectively supported on both sides of the foundation pit when in use, and are arranged along the extension direction of the foundation pit, and the supporting walls 1 form a corrugated structure as a whole.

[0027] Exemplarily, each row of the supporting wall 1 may be configured to include thirty Larsen steel sheet piles 11, and adjacent Larsen steel sheet piles 11 are centrally symmetrically arranged.

[0028] When in use, the lower half of the Larsen steel sheet pile 11 is vertically inserted into the soil; the first pressing portion 12 is formed on the inner convex surface of the Larsen steel sheet pile 11 with the convex end facing inward, and the second pressing portion 13 is formed on the inner concave surface of the Larsen steel sheet pile 11 with the convex end facing outward; Figure 2 As shown, both sides of the Larsen steel sheet pile 11 have hook ends, and the hook ends are arranged in a quasi-L-shaped structure, and the hook ends of the Larsen steel sheet pile 11 with the convex end facing inward are arranged inward, and the hook ends of the Larsen steel sheet pile 11 with the convex end facing outward are arranged outward, and the hook ends of the adjacent Larsen steel sheet piles 11 with the convex end facing inward and the hook ends of the Larsen steel sheet piles 11 with the convex end facing outward are hooked together, so that when the support rod 21 is only supported on the Larsen steel sheet pile 11 with the convex end facing inward, the Larsen steel sheet pile 11 with the convex end facing inward and the Larsen steel sheet pile 11 with the convex end facing outward have a tendency to separate under the push of the support rod 21, which will cause the support of the Larsen steel sheet pile 11 with the convex end facing outward to be unstable.

[0029] The pressure bearing seat 2 is configured as a strip structure, and the cross-sectional shape is configured as a rectangle. The pressure bearing seat 2 is configured horizontally and parallel to the wall surface of the supporting wall 1 when in use.

[0030] It can be understood that the two pressure bearing seats 2 can be arranged to be connected via a frame.

[0031] like Figure 5As shown, the support rod 21 is arranged as a T-shaped structure, and has a first columnar part and a plate-like part, wherein the axis of the first columnar part is perpendicular to the wall surface of the supporting wall 1 during installation, and the inner end is slidably inserted into the pressure-bearing seat 2, and the outer end is suspended on the outside of the pressure-bearing seat 2; the plate-like part is vertically installed on the outer end of the first columnar part, and when in use, it is pushed on the inner convex surface of the Larsen steel sheet pile 11 with the convex end facing inward or the inner concave surface of the Larsen steel sheet pile 11 with the convex end facing outward.

[0032] Exemplarily, the number of support rods 21 can be set to twenty and divided into two groups. The two groups of support rods 21 are respectively inserted into two pressure seats 2, and the ten support rods 21 in the same group are arranged at intervals along the extension direction of the pressure seat 2.

[0033] It can be understood that in order to facilitate the support rod 21 to abut on the first abutting portion 12 or the second abutting portion 13, the length of the first columnar portion of the support rod 21 can be adaptively adjusted; specifically, since the distance between the first abutting portion 12 and the center of the foundation pit is relatively close, the length of the first columnar portion of the support rod 21 corresponding to the first abutting portion 12 can be correspondingly set to be shorter; since the distance between the second abutting portion 13 and the center of the foundation pit is relatively far, the length of the first columnar portion of the support rod 21 corresponding to the second abutting portion 13 can be correspondingly set to be longer.

[0034] During use, the edge of the foundation pit is first supported by two rows of supporting walls 1, and then the two pressure-bearing seats 2 are respectively placed on the inner sides of the two rows of supporting walls 1, and then the support rods 21 are driven to slide along the wall direction perpendicular to the supporting wall 1 and in the direction close to the supporting wall 1, so as to push on the inner convex surface of the Larsen steel sheet pile 11 with the convex end facing inward or the inner concave surface of the Larsen steel sheet pile 11 with the convex end facing outward, so that all the Larsen steel sheet piles 11 can simultaneously rely on the support of the support rods 21, their own rigidity and the part inserted into the soil to support the foundation pit, thereby helping to improve the reliability during support.

[0035] In a further embodiment, in order to improve the sealing performance of the supporting wall 1, the supporting force generated by the supporting rod 21 supported on the first pressing portion 12 is F1, and the supporting force generated by the supporting rod 21 supported on the second pressing portion 13 is F2, and F1<F2.

[0036] During use, under the push of the support rod 21, the Larsen steel sheet pile 11 with the convex end facing inward and the Larsen steel sheet pile 11 with the convex end facing outward both have a tendency to move outward. Since the supporting force F1 generated by the support rod 21 supported on the Larsen steel sheet pile 11 with the convex end facing inward is smaller than the supporting force F2 generated by the support rod 21 supported on the Larsen steel sheet pile 11 with the convex end facing outward, the Larsen steel sheet pile 11 supported on the convex end facing outward has a tendency to move outward relative to the Larsen steel sheet pile 11 with the convex end facing inward, and thus the Larsen steel sheet pile 11 with the convex end facing outward and the Larsen steel sheet pile 11 with the convex end facing inward have a tendency to be clamped by the mutually engaged hook ends, thereby improving the connection stability between the two adjacent Larsen steel sheet piles 11 and the stability during support, and also improving the sealing, thereby reducing the amount of external water and soil penetrating into the foundation pit through the gap between the two adjacent Larsen steel sheet piles 11, which is beneficial to improving the reliability of support.

[0037] In other embodiments, the supporting mechanism for foundation pit excavation is configured to further include a hydraulic drive assembly, and the hydraulic drive assembly is configured to provide a driving force for the support rod 21 to slide.

[0038] When in use, the support rod 21 is driven by the hydraulic drive assembly to slide in a direction perpendicular to the wall surface of the supporting wall 1 and toward the supporting wall 1, so as to push against the inner convex surface of the Larsen steel sheet pile 11 with the convex end facing inward or the inner concave surface of the Larsen steel sheet pile 11 with the convex end facing outward, thereby supporting the foundation pit through the supporting wall 1.

[0039] In a further embodiment, the hydraulic drive assembly is configured to include a plurality of hydraulic cylinder bodies 3 , which are inserted into the pressure-bearing seat 2 and configured to receive hydraulic fluid from the outside; the support rod 21 is inserted into the hydraulic cylinder body 3 .

[0040] Specifically in this embodiment, Figure 5 As shown, the hydraulic cylinder body 3 is arranged as a T-shaped structure, and has a second columnar part and a block part. The outer end of the block part is fixedly mounted on the inner side wall of the pressure-bearing seat 2 close to the supporting wall 1, and the inner end is suspended. The outer end of the second columnar part is vertically mounted on the inner end of the block part, and the inner end is suspended. A columnar sink groove is opened on the outer side wall of the pressure-bearing seat 2 close to the supporting wall 1, and the columnar sink groove passes through the block part and the second columnar part in turn inward, and is coaxially arranged with the second columnar part.

[0041] Exemplarily, the number of hydraulic cylinder bodies 3 can be set to twenty, and they are evenly divided into two groups. The two groups of hydraulic cylinder bodies 3 are respectively inserted in two pressure-bearing seats 2, and the ten hydraulic cylinder bodies 3 in the same group are arranged at intervals along the extension direction of the pressure-bearing seat 2. When installing, the first columnar part of the support rod 21 is inserted in the columnar groove; accordingly, each pressure-bearing seat 2 is provided with ten columnar grooves, and the ten columnar grooves are arranged at intervals along the extension direction of the pressure-bearing seat 2.

[0042] More specifically, in order to facilitate the supply of hydraulic fluid to the hydraulic cylinder 3, the support mechanism for foundation pit excavation can be configured to include twenty first hydraulic pumps, and the pumping ends of the first hydraulic pumps are connected to the columnar sinks.

[0043] It will be appreciated that the hydraulic fluid may be provided as hydraulic oil.

[0044] During use, when the two pressure-bearing seats 2 are respectively placed on the inner sides of the two rows of supporting walls 1, the first hydraulic pump is started, and the first hydraulic pump pumps hydraulic oil into the hydraulic cylinder 3. Under the action of the hydraulic pressure, the support rod 21 slides along the wall direction perpendicular to the supporting wall 1 and in the direction close to the supporting wall 1, so as to push on the inner convex surface of the Larsen steel sheet pile 11 with the convex end facing inward or the inner concave surface of the Larsen steel sheet pile 11 with the convex end facing outward, and then support the foundation pit through the supporting wall 1.

[0045] It can be understood that in order to make the supporting force F1 generated by the support rod 21 supported on the Larsen steel sheet pile 11 with the convex end facing inward smaller than the supporting force F2 generated by the support rod 21 supported on the Larsen steel sheet pile 11 with the convex end facing outward, it can be set that the pump oil pressure of the first hydraulic pump corresponding to the support rod 21 supported on the Larsen steel sheet pile 11 with the convex end facing inward is smaller than the pump oil pressure of the first hydraulic pump corresponding to the support rod 21 supported on the Larsen steel sheet pile 11 with the convex end facing outward.

[0046] In a further embodiment, due to differences in soil structure, soil moisture, and environment, some of the soil supported by the Larsen steel sheet piles 11 may not require the additional supporting force provided by the support rods 21. When the supporting force of the support rods 21 is applied to this part of the soil, the upper half of the Larsen steel sheet pile 11 is simultaneously subjected to the outward supporting force from the support rods 21 and the supporting force from the lower half of the Larsen steel sheet pile 11, and the lower half of the Larsen steel sheet pile 11 is subjected to the inward thrust of the soil, so that the upper and lower forces of the Larsen steel sheet pile 11 are uneven, and the force applied to the upper half is greater than the force applied to the lower half. Under the combined force, the Larsen steel sheet pile 11 tends to tilt outward, which can easily cause damage to the Larsen steel sheet pile 11. To solve this problem, the support mechanism configured for foundation pit excavation also includes a cut-off assembly 4, which is configured to cut off the hydraulic pressure of the hydraulic fluid on the support rod 21 when the support rod 21 moves outward a distance greater than or equal to a preset distance.

[0047] Specifically in this embodiment, the preset distance can be set according to needs, such as 1mm, 2mm, etc.; when the distance the support rod 21 moves outward is greater than or equal to the preset distance, it means that the soil outside the Larsen steel sheet pile 11 pushed by the support rod 21 belongs to the above-mentioned situation where the additional supporting force brought by the support rod 21 is not required. In order to avoid damage to the Larsen steel sheet pile 11, it is set that when the support rod 21 moves outward, the hydraulic pressure of the hydraulic fluid on the support rod 21 is cut off by the cut-off component 4, so that the support rod 21 no longer supports the corresponding Larsen steel sheet pile 11, thereby avoiding damage to the Larsen steel sheet pile 11.

[0048] In a further embodiment, the cut-off assembly 4 is configured to include two cut-off pieces 41, which are inserted into the hydraulic cylinder body 3 and are respectively located on both sides of the liquid flow channel in the hydraulic cylinder body 3. The cut-off pieces 41 can elastically slide in a direction perpendicular to the liquid flow channel, and have corresponding first positions and second positions before and after sliding. When in the first position, the two cut-off pieces 41 are stopped at both sides of the support rod 21 at the same time; when in the second position, the two cut-off pieces 41 are sealed and abutted.

[0049] Specifically in this embodiment, in order to facilitate the installation of the cut-off piece 41, as shown in FIG. Figure 7 As shown, two connecting channels 301 are symmetrically opened in the block portion of the hydraulic cylinder body 3. The connecting channel 301 is arranged to be a C-shaped structure when viewed from a top view, and the opening faces the support rod 21. Both ends of the connecting channel 301 are vertically connected to the columnar sink groove. The truncation pieces 41 are respectively slidably inserted into the outer ends of the connecting channel 301 and can slide along the axial direction perpendicular to the columnar sink groove.

[0050] In order to facilitate the elastic sliding of the cutting piece 41, the cutting component 4 is configured to further include two compression springs 42, such as Figure 7 As shown, the compression spring 42 is horizontally inserted into the outer end of the connecting channel 301 and connected between the truncation piece 41 and the block portion of the hydraulic cylinder body 3. Under the action of the compression spring 42, the truncation piece 41 has a tendency to be inserted into the columnar sink.

[0051] It can be understood that when the number of the support rods 21 is set to twenty, the number of the cut-off components 4 is also set to twenty accordingly.

[0052] Initially, the truncation piece 41 is in the first position and is pushed against the circumferential side wall of the first columnar portion of the support rod 21 .

[0053] During the process of the first hydraulic pump pumping hydraulic oil into the hydraulic cylinder body 3, the support rod 21 slides in a direction perpendicular to the wall surface of the supporting wall 1 and in a direction close to the supporting wall 1 under the action of hydraulic pressure; when the soil outside the Larsen steel sheet pile 11 pushed by the support rod 21 does not belong to the above-mentioned situation where the additional supporting force brought by the support rod 21 is not required, the support rod 21 is normally pushed on the inner convex surface of the Larsen steel sheet pile 11 with the convex end facing inward or the inner concave surface of the Larsen steel sheet pile 11 with the convex end facing outward, so as to support the foundation pit through the supporting wall 1.

[0054] When the soil outside the Larsen steel sheet pile 11 pushed by the support rod 21 belongs to the above-mentioned situation where the additional supporting force brought by the support rod 21 is not needed, when the support rod 21 moves outward by a preset distance under the action of hydraulic pressure, the end of the first columnar part of the support rod 21 passes over the cut-off piece 41. At this time, under the action of the compression spring 42, the two cut-off pieces 41 in the hydraulic cylinder body 3 can be inserted into the columnar sink groove and achieve sealed abutment. At this time, the hydraulic oil in the hydraulic cylinder body 3 is divided into two streams, one of which is in contact with the support rod 21, and the hydraulic pressure is zero, so that the support rod 21 no longer supports the corresponding Larsen steel sheet pile 11, avoiding damage to the Larsen steel sheet pile 11; the other stream does not contact the support rod 21, and the hydraulic pressure is normal.

[0055] In a further embodiment, in order to improve the sealing performance when the two cut-off pieces 41 abut against each other, the abutting surfaces of the two cut-off pieces 41 are configured to be keyed.

[0056] Specifically in this embodiment, the abutting surface of the truncation piece 41 can be set to any shape that can be spliced ​​with each other, such as S-shape, L-shape, C-shape, zigzag shape, wave shape, etc.

[0057] In other embodiments, in order to improve the convenience of adjustment, all the hydraulic cylinder bodies 3 in the same group are arranged to be interconnected.

[0058] Specifically in this embodiment, Figure 5 As shown, a connecting pipe 22 is inserted into the pressure-bearing seat 2, and the connecting pipe 22 is connected to the inner ends of all the columnar sinks at the same time.

[0059] It can be understood that, in order to facilitate the supply of hydraulic fluid to the hydraulic cylinder 3 , the supporting mechanism for foundation pit excavation can be configured to include a second hydraulic pump, and the pumping end of the second hydraulic pump is connected to the connecting pipe 22 .

[0060] It can be understood that in order to make the supporting force F1 generated by the support rod 21 supported on the Larsen steel sheet pile 11 with the convex end facing inward smaller than the supporting force F2 generated by the support rod 21 supported on the Larsen steel sheet pile 11 with the convex end facing outward, it can be set that the radius of the first columnar portion of the support rod 21 supported on the Larsen steel sheet pile 11 with the convex end facing inward is smaller than the radius of the first columnar portion of the support rod 21 supported on the Larsen steel sheet pile 11 with the convex end facing outward.

[0061] Specifically, since all the hydraulic cylinder bodies 3 in the same group are interconnected, the pressure of the hydraulic oil filled in all the hydraulic cylinder bodies 3 is equal. Since the radius of the first columnar portion of the support rod 21 supported on the Larsen steel sheet pile 11 with the convex end facing inward is smaller than the radius of the first columnar portion of the support rod 21 supported on the Larsen steel sheet pile 11 with the convex end facing outward, the inner end area of ​​the first columnar portion of the support rod 21 supported on the Larsen steel sheet pile 11 with the convex end facing inward is smaller than the inner end area of ​​the first columnar portion of the support rod 21 supported on the Larsen steel sheet pile 11 with the convex end facing outward (S=πr). Since the supporting force generated by the support rod 21 is equal to the pressure of the hydraulic oil multiplied by the inner end area of ​​the first columnar portion of the support rod 21 (F=PS), the supporting force F1 generated by the support rod 21 supported on the Larsen steel sheet pile 11 with the convex end facing inward is smaller than the supporting force F2 generated by the support rod 21 supported on the Larsen steel sheet pile 11 with the convex end facing outward.

[0062] In other embodiments, the support mechanism for foundation pit excavation is configured to also include a hydraulic drive component, which is configured to provide a driving force for the two pressure-bearing seats 2 to move synchronously in directions away from or toward each other, so as to adapt to two rows of support walls 1 with different spacings.

[0063] Specifically in this embodiment, the hydraulic driving component can be set as a manual hydraulic bidirectional driving cylinder or an electric bidirectional hydraulic driving cylinder 5.

[0064] More specifically, Figure 1 As shown, the electric bidirectional hydraulic drive cylinder 5 and the two pressure bearing seats 2 together form an "I"-shaped structure.

[0065] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0066] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. It should be pointed out that for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A support mechanism for foundation pit excavation, characterized in that: The support mechanism for foundation pit excavation includes a support wall, which has two rows. Each row of the support walls includes a plurality of Larsen steel sheet piles. The relatively convex portion on the inner side of the support wall serves as a first pressure portion, and the relatively concave portion on the inner side of the support wall serves as a second pressure portion. Pressure seats are provided on the inner sides of the two rows of support walls, and a plurality of support rods are provided on each of the pressure seats. The support rods can slide in a direction perpendicular to the wall surface of the support wall to support on the first pressure portion or the second pressure portion.

2. The supporting mechanism for foundation pit excavation according to claim 1, characterized in that: The supporting force generated by the supporting rod supported on the first pressing portion is F1, and the supporting force generated by the supporting rod supported on the second pressing portion is F2, and F1<F2.

3. The supporting mechanism for foundation pit excavation according to claim 1, characterized in that: The supporting mechanism for foundation pit excavation also includes a hydraulic drive assembly, which is configured to provide a driving force for the sliding of the support rod.

4. The supporting mechanism for foundation pit excavation according to claim 3, characterized in that: The hydraulic drive assembly includes a plurality of hydraulic cylinder bodies, the hydraulic cylinder bodies are inserted into the pressure-bearing seat and are configured to receive hydraulic fluid from the outside; the support rods are inserted into the hydraulic cylinder bodies.

5. The supporting mechanism for foundation pit excavation according to claim 4, characterized in that: The support mechanism for foundation pit excavation also includes a cut-off component, which is configured to cut off the hydraulic pressure of the hydraulic fluid on the support rod when the distance the support rod moves outward is greater than or equal to a preset distance.

6. The supporting mechanism for foundation pit excavation according to claim 5, characterized in that: The cut-off assembly includes two cut-off pieces, which are inserted into the hydraulic cylinder body and are respectively located on both sides of the liquid flow channel in the hydraulic cylinder body. The cut-off pieces can elastically slide in a direction perpendicular to the liquid flow channel, and have corresponding first positions and second positions before and after sliding. When in the first position, the two cut-off pieces are stopped on both sides of the support rod at the same time; when in the second position, the two cut-off pieces are sealed and abutted.

7. The supporting mechanism for foundation pit excavation according to claim 6, characterized in that: The abutting surfaces of the two truncated pieces are keyed together.

8. The supporting mechanism for foundation pit excavation according to claim 4, characterized in that: All the hydraulic cylinder bodies in the same group are communicated with each other.

9. The supporting mechanism for foundation pit excavation according to claim 1, characterized in that: The support mechanism for foundation pit excavation also includes a hydraulic drive component, which is configured to provide a driving force for the two pressure-bearing seats to move synchronously in directions away from or towards each other, so as to adapt to the two rows of support walls with different spacings.

10. The supporting mechanism for foundation pit excavation according to claim 9, characterized in that: The hydraulic drive member is a manual hydraulic bidirectional drive cylinder or an electric bidirectional hydraulic drive cylinder.

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