Foundation pit support and its construction method using inclined pile support

Abstract

The present invention discloses a foundation pit support and a construction method thereof using inclined pile support, aiming to provide a foundation pit support and a construction method thereof which can complete the construction of inclined piles before foundation pit excavation, so as to realize the one-time completion of foundation pit excavation operation while ensuring the stability of foundation pit support, thereby optimizing the construction process steps and accelerating the total construction period of foundation pit. The foundation pit support construction method using inclined pile support includes the following steps in sequence: A, foundation pit support pile construction, which is to construct foundation pit support piles at the edge of the foundation pit; B, inclined pile construction, which is to construct inclined cement soil mixing piles in the foundation pit soil layer inside the foundation pit support piles before foundation pit excavation; then, before the cement soil mixing piles are hardened, inclined steel piles are inserted into the cement soil mixing piles; C, capping beam construction, which is to pour concrete along the upper end of the foundation pit support piles to form a capping beam before foundation pit excavation, and the top of the inclined steel piles is poured in the capping beam.

Description

Technical Field

[0001] The invention relates to the field of foundation pit support, and in particular to a foundation pit support using inclined piles and a construction method thereof. Background Art

[0002] In order to ensure the safety of the underground structure and the surrounding environment of the foundation pit, it is necessary to adopt support, reinforcement and other protective measures on the side walls and around the foundation pit. The current foundation pit support system usually includes a circle of foundation pit retaining piles set around the edge of the foundation pit, a capping beam extending along the upper end of the foundation pit retaining piles, and a horizontal support beam set between the capping beams, wherein the retaining piles are generally formed by a number of cement-soil mixing piles that are interlocked and connected in sequence; the capping beam is cast with concrete, and the upper ends of the cement-soil mixing piles that constitute the retaining piles are connected as a whole; the horizontal support beam is supported between the capping beams on the opposite sides of the foundation pit, thereby forming a support for the foundation pit and ensuring the support strength of the foundation pit support system. The current foundation pit support system uses horizontal support beams for support. For large-area foundation pits, the length of the horizontal support beam is long, which makes the cost of the horizontal support beam high on the one hand, and on the other hand, the horizontal support beam spans the foundation pit, and it is necessary to set a number of columns for supporting the horizontal support beam below the horizontal support beam, which occupies a large space and is not conducive to excavation and foundation pit main structure operations.

[0003] In order to solve the above-mentioned deficiencies of using horizontal support beams for support in foundation pit support systems, some foundation pits currently use inclined supports. Although the inclined supports can effectively solve the problem that horizontal supports occupy a large space and are not conducive to excavation and main structure operations of the foundation pit; however, the current inclined supports cannot be constructed before foundation pit excavation, and it is necessary to first construct foundation pit retaining piles and top pressure beams; then basin excavation is adopted, that is, the soil in the middle of the foundation pit is first excavated, and a large area of ​​counter-pressure soil must be reserved on the edge of the foundation pit to resist the soil pressure, and then the large bottom plate in the foundation pit is poured; then, after the outer side of the large bottom plate in the foundation pit is poured, the inclined supports can be erected. , and then the reserved soil on the side of the foundation pit below the inclined support can be excavated; in this way, when the foundation pit excavation operation is carried out to a certain extent, it is necessary to stop the excavation operation, and then carry out the construction and erection of the inclined support again, and then carry out the excavation operation again. This process requires the scheduling of various construction equipment and the arrangement of different operators, which will extend the construction period; and in the process of foundation pit excavation, attention should be paid to the soil layer to be reserved on the side of the foundation pit. Once the soil layer to be reserved on the side of the foundation pit is excavated too much, it may cause the foundation pit retaining piles to bend, crack, or even break under the action of the external soil pressure. On the other hand, in the process of digging the reserved soil on the side of the foundation pit, excavators and earthmoving vehicles will inevitably roll over the large bottom plate of the pit structure that has been completed, causing damage to the completed area. Summary of the invention

[0004] The purpose of the present invention is to provide a foundation pit enclosure and a construction method thereof that can complete the construction of inclined piles before foundation pit excavation, thereby achieving one-time completion of the foundation pit excavation operation while ensuring the stability of the foundation pit support, thereby optimizing the construction process steps and speeding up the total construction period of the foundation pit.

[0005] The technical solution of the present invention is:

[0006] A foundation pit retaining construction method using inclined pile support comprises the following steps in sequence:

[0007] A. Construction of foundation pit retaining piles: Construction of foundation pit retaining piles at the edge of the foundation pit;

[0008] B. Inclined pile construction: Before the excavation of the foundation pit, inclined cement-soil mixing piles are constructed in the foundation pit soil layer inside the foundation pit retaining piles. The upper end of the cement-soil mixing pile is close to the upper end of the foundation pit retaining pile or intersects with the upper end of the foundation pit retaining pile, and the lower end of the cement-soil mixing pile is inclined toward the middle of the foundation pit;

[0009] Next, before the cement soil mixing pile hardens, an inclined steel pile is inserted into the cement soil mixing pile along the inclined direction of the cement soil mixing pile, and the cement soil mixing pile and the inclined steel pile together constitute an inclined pile;

[0010] C. Construction of capping beam: Before excavation of foundation pit, concrete is poured along the upper end of foundation pit retaining piles to form capping beam, and the top of inclined steel piles is poured in the capping beam so that the upper end of foundation pit retaining piles and the upper end of inclined piles are connected as a whole through the capping beam.

[0011] The inclined pile construction in the foundation pit retaining construction method of this scheme adopts the method of constructing inclined cement soil mixing piles in the foundation pit soil layer inside the foundation pit retaining piles before the foundation pit is excavated, and then inserting inclined steel piles into the cement soil mixing piles to form inclined piles (the construction of cement soil mixing piles can be beneficial to the insertion of inclined steel piles on the one hand, and on the other hand, after the cement soil mixing piles are hardened, the bonding force between the inclined piles and the surrounding soil layer can be effectively improved, and the supporting capacity of the inclined piles can be improved), and the upper end of the foundation pit retaining piles is connected to the upper end of the inclined piles by a top pressure beam, so as to complete the inclined piles before the foundation pit is excavated. During construction, the top beam and the upper ends of the foundation pit retaining piles are connected with the upper ends of the inclined piles to ensure the stability of the foundation pit support. Therefore, the foundation pit excavation operation can be completed at one time while ensuring the stability of the foundation pit support, and then the large structural bottom plate of the foundation pit can be constructed. There is no need to excavate in steps, and there is no need to reserve a large area of ​​counter-pressure soil at the edge of the foundation pit to resist the soil pressure. The construction process steps can be effectively optimized, and the overall construction period of the foundation pit can be accelerated. At the same time, there is no problem that excavators and earth-moving vehicles will inevitably roll over the completed large structural bottom plate of the foundation pit, causing damage to the completed area.

[0012] Preferably, the inclined steel pile is provided with an anti-deviation warning device, which includes a main sleeve arranged on the inclined steel pile, a warning steel bar sliding along the main sleeve, a baffle and a limit block arranged on the warning steel bar, and a pre-tensioning compression spring sleeved on the warning steel bar, the baffle being located below the main sleeve, one end of the pre-tensioning compression spring being against the baffle, and the other end of the pre-tensioning compression spring being against the main sleeve, the limit block being located above the main sleeve, and the limit block being against the main sleeve under the action of the pre-tensioning compression spring, the warning steel bar being parallel to the inclined steel pile, the upper end of the warning steel bar being close to the upper end of the inclined steel pile, the lower end of the warning steel bar extending below the lower end of the inclined steel pile, and a resistance member being provided on the warning steel bar and below the lower end of the inclined steel pile.

[0013] Since the depth of the cement-soil mixing pile is deep, the insertion depth of the inclined steel pile is also deep. During the process of inserting the inclined steel pile into the cement-soil mixing pile, once the insertion angle of the inclined steel pile is inconsistent with the inclination angle of the cement-soil mixing pile, part or a large part of the inclined steel pile will be inserted into the soil layer, resulting in the separation of the inclined steel pile and the cement-soil mixing pile. They cannot be well combined into one, thus affecting the supporting capacity of the inclined pile. In order to solve this problem, the inventor set an anti-deviation warning device on the inclined steel pile. Specifically,

[0014] Since the cement-soil mixing pile is formed by mixing, the resistance of the inclined steel pile inserted into the cement-soil mixing pile before hardening is much smaller than the resistance of inserting into the soil layer of the foundation pit; in this way, in the process of inserting the inclined steel pile into the cement-soil mixing pile, if the insertion angle of the inclined steel pile is consistent with the inclination angle of the cement-soil mixing pile, then in this process, no displacement occurs between the early warning steel bar and the inclined steel pile, that is to say, in the process of inserting the inclined steel pile into the cement-soil mixing pile, if no displacement occurs between the early warning steel bar and the inclined steel pile, it means that the insertion angle of the inclined steel pile is consistent with the inclination angle of the cement-soil mixing pile; if the insertion angle of the inclined steel pile is inconsistent with the inclination angle of the cement-soil mixing pile, then in this process, the early warning steel bar The lower end of will be inserted into the foundation pit soil layer. When the resistance piece enters the foundation pit soil layer, the resistance of the foundation pit soil layer on the resistance piece will overcome the force of the preloaded compression spring, causing the early warning steel bar to move up relative to the inclined steel pile. That is to say, in the process of the inclined steel pile being inserted into the cement soil mixing pile, if the early warning steel bar moves up relative to the inclined steel pile, it means that the insertion angle of the inclined steel pile is inconsistent with the inclination angle of the cement soil mixing pile. At this time, the inclined steel pile can be pulled out, and the insertion angle of the inclined steel pile can be readjusted before continuing to be inserted until no displacement occurs between the early warning steel bar and the inclined steel pile during the process of the inclined steel pile being inserted into the cement soil mixing pile, thereby ensuring that the inclined steel pile and the cement soil mixing pile are reliably combined into one.

[0015] Preferably, the main guide sleeve is close to the upper end of the inclined steel pile, and the main guide sleeve is fixed to the inclined steel pile by bolts. In this way, after the inclined steel pile is inserted into the cement soil mixing pile as required, the main guide sleeve near the upper end of the inclined steel pile can be disassembled, and then the main guide sleeve, the warning steel bar and the pre-tightening compression spring can be pulled out from the cement soil mixing pile for recycling.

[0016] Preferably, the anti-deviation warning device further comprises a lower guide sleeve arranged on the inclined steel pile, the lower guide sleeve is close to the lower end of the inclined steel pile, and the warning steel bar passes through the lower guide sleeve. In this way, the lower guide sleeve can cooperate with the main guide sleeve to guide the warning steel bar.

[0017] Preferably, an extension steel bar is provided at the lower end of the early warning steel bar, the extension steel bar is coaxial with the early warning steel bar, the outer diameter of the extension steel bar is smaller than the outer diameter of the early warning steel bar, the resistance piece is provided with a plug hole, the extension steel bar is inserted into the plug hole, and the resistance piece is against the lower end surface of the early warning steel bar. In this way, after the inclined steel pile is inserted into the cement soil mixing pile as required, the main sleeve, the early warning steel bar and the pre-tightening compression spring can be pulled out of the cement soil mixing pile without affecting the pullout.

[0018] Preferably, the inclination angle of the cement soil mixing pile is 40-75 degrees.

[0019] Preferably, the inclined steel piles are H-shaped steels, round steel pipes, square steel pipes, or steel lattice columns.

[0020] A foundation pit retaining construction method using inclined pile support comprises the following steps in sequence:

[0021] A. Construction of foundation pit retaining piles: Construction of foundation pit retaining piles at the edge of the foundation pit;

[0022] B. Inclined pile construction: before excavation of the foundation pit, inclined steel piles with inclined distribution are inserted into the foundation pit soil layer inside the foundation pit retaining piles. The upper end of the inclined steel pile is close to the upper end of the foundation pit retaining pile or intersects with the upper end of the foundation pit retaining pile, and the lower end of the inclined steel pile is inclined toward the middle of the foundation pit. The inclined steel piles constitute inclined piles;

[0023] C. Construction of capping beam: Before excavation of foundation pit, concrete is poured along the upper end of foundation pit retaining piles to form capping beam, and the top of inclined steel piles is poured in the capping beam so that the upper end of foundation pit retaining piles and the upper end of inclined piles are connected as a whole through the capping beam.

[0024] The foundation pit retaining construction method of this scheme is suitable for use in foundation pits with soft soil. Before the foundation pit is excavated, inclined steel piles are inserted into the foundation pit soil layer inside the foundation pit retaining piles to form inclined piles, and the upper ends of the foundation pit retaining piles are connected to the upper ends of the inclined piles through the top pressure beam, thereby completing the construction of the inclined piles before the foundation pit is excavated, and connecting the upper ends of the top pressure beam and the foundation pit retaining piles to the upper ends of the inclined piles to ensure the stability of the foundation pit support; therefore, thereafter, the foundation pit excavation operation can be completed at one time while ensuring the stability of the foundation pit support, and then the structural large bottom plate of the foundation pit can be constructed, without the need for step-by-step excavation, and without reserving a large area of ​​counter-pressure soil at the edge of the foundation pit to resist the soil pressure, which can effectively optimize the construction process steps and speed up the overall construction period of the foundation pit. At the same time, there is no problem that excavators and earthmoving vehicles will inevitably roll over the completed structural large bottom plate of the foundation pit, causing damage to the completed area.

[0025] Preferably, the inclined steel piles are H-shaped steels, round steel pipes, square steel pipes, or steel lattice columns.

[0026] A foundation pit retaining system supported by inclined piles comprises foundation pit retaining piles distributed along the edge of the foundation pit, inclined piles located inside the foundation pit retaining piles and capping beams extending along the upper ends of the foundation pit retaining piles, the inclined piles comprising cement soil mixing piles arranged in the foundation pit soil layer inside the foundation pit retaining piles and inclined steel piles inserted in the cement soil mixing piles, the cement soil mixing piles being distributed in an inclined manner, the upper ends of the cement soil mixing piles being close to the upper ends of the foundation pit retaining piles or intersecting with the upper ends of the foundation pit retaining piles, the lower ends of the cement soil mixing piles being inclined toward the middle of the foundation pit, and the tops of the inclined steel piles being buried in the capping beam so that the upper ends of the foundation pit retaining piles and the upper ends of the inclined piles are connected as a whole through the capping beam. The inclined piles of the foundation pit protection of this scheme include cement soil mixing piles arranged in the foundation pit soil layer inside the foundation pit protection piles and inclined steel piles inserted in the cement soil mixing piles. In this way, it is possible to construct inclined cement soil mixing piles in the foundation pit soil layer inside the foundation pit protection piles before the foundation pit is excavated, and then insert inclined steel piles into the cement soil mixing piles to form inclined piles, and connect the upper ends of the foundation pit protection piles with the upper ends of the inclined piles through the top pressure beam, so as to complete the construction of the inclined piles before the foundation pit is excavated, and make the top pressure beam and the foundation pit protection piles The upper end is connected with the upper end of the inclined pile to ensure the stability of the foundation pit support; therefore, thereafter, the foundation pit excavation operation can be completed at one time while ensuring the stability of the foundation pit support, and then the structural large bottom plate of the foundation pit can be constructed. There is no need to excavate in steps, and there is no need to reserve a large area of ​​counter-pressure soil at the edge of the foundation pit to resist the soil pressure. The construction process steps can be effectively optimized and the overall construction period of the foundation pit can be accelerated. At the same time, there is no problem that excavators and earth-moving vehicles will inevitably roll over the completed structural large bottom plate of the foundation pit, causing damage to the completed area.

[0027] The beneficial effect of the present invention is that the construction of inclined piles can be completed before foundation pit excavation, so that the foundation pit excavation operation can be completed at one time while ensuring the stability of the foundation pit support, thereby optimizing the construction process steps and accelerating the total construction period of the foundation pit. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a structural schematic diagram of the foundation pit enclosure using inclined pile support before foundation pit excavation in the specific embodiment 1 and the specific embodiment 2 of the present invention.

[0029] Figure 2 It is a structural schematic diagram of the foundation pit retaining using inclined pile support in the specific embodiment 1 and the specific embodiment 2 of the present invention after the foundation pit is excavated to the foundation pit bottom elevation.

[0030] Figure 3 It is a partial structural schematic diagram of the inclined steel pile and the anti-deviation warning device of the specific embodiment 2 of the present invention.

[0031] In the figure:

[0032] Foundation pit retaining pile 1;

[0033] Inclined pile 2, cement soil mixing pile 2.1, inclined steel pile 2.2;

[0034] Top beam 3;

[0035] Anti-deviation warning device 4, main guide sleeve 4.1, warning steel bar 4.2, baffle 4.3, limit block 4.4, pre-tightening compression spring 4.5, lower guide sleeve 4.6, resistance piece 4.7, extension steel bar 4.8. DETAILED DESCRIPTION

[0036] Specific embodiment 1: Figure 1 , Figure 2 As shown, a foundation pit retaining device supported by inclined piles includes foundation pit retaining piles 1 distributed along the edge of the foundation pit, inclined piles 2 located on the inner side of the foundation pit retaining piles, and a capping beam 3 extending along the upper end of the foundation pit retaining piles. In this embodiment, the foundation pit retaining piles are formed by a number of mixing piles that are interlocked and connected in sequence, and the capping beam is cast with concrete, and the capping beam connects the upper ends of the mixing piles that constitute the foundation pit retaining piles into one. The inclined piles include cement soil mixing piles 2.1 arranged in the foundation pit soil layer on the inner side of the foundation pit retaining piles and inclined steel piles 2.2 inserted in the cement soil mixing piles. The cement soil mixing piles are distributed in an inclined manner, the upper end of the cement soil mixing piles is close to the upper end of the foundation pit retaining piles or intersects with the upper end of the foundation pit retaining piles, and the lower end of the cement soil mixing piles is inclined toward the middle of the foundation pit. The inclination angle of the inclined steel pile is consistent with the inclination angle of the cement soil mixing pile. In this embodiment, the upper end of the inclined steel pile is located above the ground. The top of the inclined steel pile is buried in the capping beam so that the upper end of the foundation pit retaining pile and the upper end of the inclined pile are connected as a whole through the capping beam.

[0037] The inclined piles of the foundation pit protection of this embodiment include cement soil mixing piles arranged in the foundation pit soil layer inside the foundation pit protection piles and inclined steel piles inserted in the cement soil mixing piles. In this way, it is possible to construct inclined cement soil mixing piles in the foundation pit soil layer inside the foundation pit protection piles before the foundation pit is excavated, and then insert inclined steel piles into the cement soil mixing piles to form inclined piles, and connect the upper ends of the foundation pit protection piles with the upper ends of the inclined piles through the top pressure beam, so as to complete the construction of the inclined piles before the foundation pit is excavated, and make the top pressure beam and the foundation pit protection piles The upper end of the pile is connected with the upper end of the inclined pile to ensure the stability of the foundation pit support; therefore, thereafter, the foundation pit excavation operation can be completed at one time while ensuring the stability of the foundation pit support, and then the structural large bottom plate of the foundation pit can be constructed. There is no need to excavate in steps, and there is no need to reserve a large area of ​​counter-pressure soil at the edge of the foundation pit to resist the soil pressure. The construction process steps can be effectively optimized and the total construction period of the foundation pit can be accelerated. At the same time, there is no problem that excavators and earth-moving vehicles will inevitably roll over the completed structural large bottom plate of the foundation pit, causing damage to the completed area.

[0038] In this embodiment, the inclination angle of the cement soil mixing pile is 40-75 degrees, for example, the inclination angle of the cement soil mixing pile is 60 degrees. The inclination angle of the cement soil mixing pile refers to the angle between the cement soil mixing pile and the horizontal plane.

[0039] The inclined steel piles are H-shaped steel or circular steel pipes or square steel pipes or steel lattice columns.

[0040] In this embodiment, the lower ends of the cement-soil mixing piles and the lower ends of the inclined steel piles are both located below the elevation of the bottom of the foundation pit.

[0041] Specific embodiment 2, as Figure 1 , Figure 2 As shown, a foundation pit retaining construction method using inclined pile support includes the following steps in sequence:

[0042] A. Construction of foundation pit retaining piles: Construction of foundation pit retaining piles 1 at the edge of the foundation pit;

[0043] B. Inclined pile construction: Before the foundation pit is excavated, inclined cement-soil mixing piles 2.1 are constructed in the foundation pit soil layer inside the foundation pit retaining piles. The upper end of the cement-soil mixing pile is close to or intersects with the upper end of the foundation pit retaining pile, and the lower end of the cement-soil mixing pile is inclined toward the middle of the foundation pit.

[0044] Next, before the cement soil mixing pile hardens, an inclined steel pile 2.2 is inserted into the cement soil mixing pile along the inclined direction of the cement soil mixing pile. The cement soil mixing pile 2.1 and the inclined steel pile 2.2 together constitute an inclined pile 2. In this embodiment, the insertion angle of the inclined steel pile is consistent with the inclination angle of the cement soil mixing pile.

[0045] C. Construction of the capping beam: Before excavation of the foundation pit, concrete is poured along the upper end of the foundation pit retaining piles to form a capping beam 3. The top of the inclined steel pile is poured in the capping beam so that the upper end of the foundation pit retaining piles and the upper end of the inclined piles are connected as a whole through the capping beam.

[0046] The inclined pile construction in the foundation pit retaining construction method of this embodiment adopts the method of constructing inclined cement soil mixing piles in the foundation pit soil layer inside the foundation pit retaining piles before the foundation pit is excavated, and then inserting inclined steel piles into the cement soil mixing piles to form inclined piles (the construction of cement soil mixing piles can be beneficial to the insertion of inclined steel piles on the one hand, and on the other hand, after the cement soil mixing piles are hardened, the bonding force between the inclined piles and the surrounding soil layer can be effectively improved, and the supporting capacity of the inclined piles can be improved), and the upper end of the foundation pit retaining piles is connected to the upper end of the inclined piles by a top pressure beam, so as to complete the inclined piles before the foundation pit is excavated. The construction is carried out in a step-by-step manner, and the upper ends of the top beams and the foundation pit retaining piles are connected with the upper ends of the inclined piles to ensure the stability of the foundation pit support. Therefore, the foundation pit excavation operation can be completed at one time while ensuring the stability of the foundation pit support, and then the large structural bottom plate of the foundation pit can be constructed. There is no need to excavate in steps, and there is no need to reserve a large area of ​​counter-pressure soil at the edge of the foundation pit to resist the soil pressure. The construction process steps can be effectively optimized and the total construction period of the foundation pit can be accelerated. At the same time, there is no problem that excavators and earth-moving vehicles will inevitably roll over the completed large structural bottom plate of the foundation pit, causing damage to the completed area.

[0047] Specifically, the foundation pit retaining piles are formed by a number of mixing piles that are interlocked and connected in sequence, and the top pressure beam connects the upper ends of the mixing piles that constitute the foundation pit retaining piles into one.

[0048] The inclination angle of the cement soil mixing pile is 40-75 degrees, for example, the inclination angle of the cement soil mixing pile is 60 degrees. The inclination angle of the cement soil mixing pile refers to the angle between the cement soil mixing pile and the horizontal plane.

[0049] The inclined steel piles are H-shaped steel or circular steel pipes or square steel pipes or steel lattice columns.

[0050] In this embodiment, the lower ends of the cement-soil mixing piles and the lower ends of the inclined steel piles are both located below the elevation of the bottom of the foundation pit.

[0051] Further, such as Figure 3As shown, an anti-deviation warning device 4 is provided on the inclined steel pile 2.2. The anti-deviation warning device includes a main guide sleeve 4.1 provided on the inclined steel pile, a warning steel bar 4.2 sliding along the main guide sleeve, a baffle 4.3 and a limit block 4.4 provided on the warning steel bar, and a preloaded compression spring 4.5 sleeved on the warning steel bar. The baffle is located below the main guide sleeve, one end of the preloaded compression spring abuts against the baffle, and the other end of the preloaded compression spring abuts against the main guide sleeve. The limit block is located above the main guide sleeve, and the limit block abuts against the main guide sleeve under the action of the preloaded compression spring. The warning steel bar is parallel to the inclined steel pile. The upper end of the warning steel bar is close to the upper end of the inclined steel pile. In this embodiment, the upper end of the warning steel bar is located below the upper end of the inclined steel pile. The lower end of the warning steel bar extends below the lower end of the inclined steel pile. A resistance member 4.7 is provided on the warning steel bar and below the lower end of the inclined steel pile. Since the depth of the cement-soil mixing pile is deep, the insertion depth of the inclined steel pile is also deep. During the process of inserting the inclined steel pile into the cement-soil mixing pile, once the insertion angle of the inclined steel pile is inconsistent with the inclination angle of the cement-soil mixing pile, part or a large part of the inclined steel pile will be inserted into the soil layer, resulting in the separation of the inclined steel pile and the cement-soil mixing pile. They cannot be well combined into one, thus affecting the supporting capacity of the inclined pile. In order to solve this problem, the inventor set an anti-deviation warning device on the inclined steel pile. Specifically,

[0052] Since the cement-soil mixing pile is formed by mixing, the resistance of the inclined steel pile inserted into the cement-soil mixing pile before hardening is much smaller than the resistance of inserting into the soil layer of the foundation pit; in this way, in the process of inserting the inclined steel pile into the cement-soil mixing pile, if the insertion angle of the inclined steel pile is consistent with the inclination angle of the cement-soil mixing pile, then in this process, no displacement occurs between the early warning steel bar and the inclined steel pile, that is to say, in the process of inserting the inclined steel pile into the cement-soil mixing pile, if no displacement occurs between the early warning steel bar and the inclined steel pile, it means that the insertion angle of the inclined steel pile is consistent with the inclination angle of the cement-soil mixing pile; if the insertion angle of the inclined steel pile is inconsistent with the inclination angle of the cement-soil mixing pile, then in this process, the early warning steel bar The lower end of will be inserted into the foundation pit soil layer. When the resistance piece enters the foundation pit soil layer, the resistance of the foundation pit soil layer on the resistance piece will overcome the force of the preloaded compression spring, causing the early warning steel bar to move up relative to the inclined steel pile. That is to say, in the process of the inclined steel pile being inserted into the cement soil mixing pile, if the early warning steel bar moves up relative to the inclined steel pile, it means that the insertion angle of the inclined steel pile is inconsistent with the inclination angle of the cement soil mixing pile. At this time, the inclined steel pile can be pulled out, and the insertion angle of the inclined steel pile can be readjusted before continuing to be inserted until no displacement occurs between the early warning steel bar and the inclined steel pile during the process of the inclined steel pile being inserted into the cement soil mixing pile, thereby ensuring that the inclined steel pile and the cement soil mixing pile are reliably combined into one.

[0053] Further, such as Figure 3As shown, the main guide sleeve is close to the upper end of the inclined steel pile, and the main guide sleeve is fixed to the inclined steel pile by bolts. In this way, after the inclined steel pile is inserted into the cement soil mixing pile as required, the main guide sleeve near the upper end of the inclined steel pile can be disassembled, and then the main guide sleeve, warning steel bar and pre-tightening compression spring can be pulled out from the cement soil mixing pile for recycling.

[0054] Further, such as Figure 3 As shown, the anti-deviation warning device also includes a lower guide sleeve 4.6 arranged on the inclined steel pile, and the lower guide sleeve is close to the lower end of the inclined steel pile. The warning steel bar passes through the lower guide sleeve. The lower end of the warning steel bar is provided with an extension steel bar 4.8, and the extension steel bar is coaxial with the warning steel bar. The outer diameter of the extension steel bar is smaller than the outer diameter of the warning steel bar. The resistance member is provided with a plug-in hole, and the extension steel bar is inserted into the plug-in hole, and the resistance member is against the lower end surface of the warning steel bar. In this embodiment, the friction force between the extension steel bar and the plug-in hole is greater than the gravity of the resistance member. The resistance member is a resistance plate or a resistance block. In this way, after the inclined steel pile is inserted into the cement soil mixing pile as required, it can be pulled out of the cement soil mixing pile without affecting the main guide sleeve, the warning steel bar and the pre-tightening compression spring.

[0055] Specific embodiment 3, a foundation pit retaining construction method using inclined pile support, comprises the following steps in sequence:

[0056] A. Construction of foundation pit retaining piles: Construction of foundation pit retaining piles at the edge of the foundation pit;

[0057] B. Inclined pile construction: before excavation of the foundation pit, inclined steel piles with inclined distribution are inserted into the foundation pit soil layer inside the foundation pit retaining piles. The upper end of the inclined steel pile is close to the upper end of the foundation pit retaining pile or intersects with the upper end of the foundation pit retaining pile, and the lower end of the inclined steel pile is inclined toward the middle of the foundation pit. The inclined steel piles constitute inclined piles;

[0058] C. Construction of capping beam: Before excavation of foundation pit, concrete is poured along the upper end of foundation pit retaining piles to form capping beam, and the top of inclined steel piles is poured in the capping beam so that the upper end of foundation pit retaining piles and the upper end of inclined piles are connected as a whole through the capping beam.

[0059] The foundation pit retaining construction method of this scheme is suitable for use in foundation pits with soft soil. Before the foundation pit is excavated, inclined steel piles are inserted into the foundation pit soil layer inside the foundation pit retaining piles to form inclined piles, and the upper ends of the foundation pit retaining piles are connected to the upper ends of the inclined piles through the top pressure beam, thereby completing the construction of the inclined piles before the foundation pit is excavated, and connecting the upper ends of the top pressure beam and the foundation pit retaining piles to the upper ends of the inclined piles to ensure the stability of the foundation pit support; therefore, thereafter, the foundation pit excavation operation can be completed at one time while ensuring the stability of the foundation pit support, and then the structural large bottom plate of the foundation pit can be constructed, without the need for step-by-step excavation, and without reserving a large area of ​​counter-pressure soil at the edge of the foundation pit to resist the soil pressure, which can effectively optimize the construction process steps and speed up the overall construction period of the foundation pit. At the same time, there is no problem that excavators and earthmoving vehicles will inevitably roll over the completed structural large bottom plate of the foundation pit, causing damage to the completed area.

[0060] Specifically, the foundation pit retaining piles are formed by a number of mixing piles that are interlocked and connected in sequence, and the top pressure beam connects the upper ends of the mixing piles that constitute the foundation pit retaining piles into one.

[0061] The inclination angle of the cement soil mixing pile is 40-75 degrees, for example, the inclination angle of the cement soil mixing pile is 60 degrees. The inclination angle of the cement soil mixing pile refers to the angle between the cement soil mixing pile and the horizontal plane.

[0062] The inclined steel piles are H-shaped steel or circular steel pipes or square steel pipes or steel lattice columns.

[0063] In this embodiment, the lower ends of the cement-soil mixing piles and the lower ends of the inclined steel piles are both located below the elevation of the bottom of the foundation pit.

[0064] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent transformation made to the above embodiment based on the technical essence of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A foundation pit retaining construction method using inclined pile support, characterized in that: The following steps are included in sequence: A. Construction of foundation pit retaining piles: Construction of foundation pit retaining piles at the edge of the foundation pit; B. Inclined pile construction: Before the excavation of the foundation pit, inclined cement-soil mixing piles are constructed in the foundation pit soil layer inside the foundation pit retaining piles. The upper end of the cement-soil mixing pile is close to the upper end of the foundation pit retaining pile or intersects with the upper end of the foundation pit retaining pile, and the lower end of the cement-soil mixing pile is inclined toward the middle of the foundation pit; Next, before the cement soil mixing pile hardens, an inclined steel pile is inserted into the cement soil mixing pile along the inclined direction of the cement soil mixing pile, and the cement soil mixing pile and the inclined steel pile together constitute an inclined pile; C. Construction of the capping beam: Before the excavation of the foundation pit, concrete is poured along the upper end of the foundation pit retaining pile to form a capping beam. The top of the inclined steel pile is poured in the capping beam, so that the upper end of the foundation pit retaining pile and the upper end of the inclined pile are connected as a whole through the capping beam; The inclined steel pile is provided with an anti-deviation warning device, which includes a main sleeve arranged on the inclined steel pile, a warning steel bar sliding along the main sleeve, a baffle and a limit block arranged on the warning steel bar, and a pre-tightening compression spring sleeved on the warning steel bar, the baffle is located below the main sleeve, and the limit block is pressed against the main sleeve under the action of the pre-tightening compression spring, the warning steel bar is parallel to the inclined steel pile, and a resistance piece is provided on the warning steel bar and below the lower end of the inclined steel pile, one end of the pre-tightening compression spring is pressed against the baffle, and the other end of the pre-tightening compression spring is pressed against the main sleeve, the limit block is located above the main sleeve, the upper end of the warning steel bar is close to the upper end of the inclined steel pile, and the lower end of the warning steel bar extends below the lower end of the inclined steel pile.

2. The foundation pit retaining construction method using inclined pile support according to claim 1 is characterized in that: The main guide sleeve is close to the upper end of the inclined steel pile, and the main guide sleeve is fixed on the inclined steel pile by bolts.

3. The foundation pit retaining construction method using inclined pile support according to claim 1 or 2 is characterized in that: The anti-deviation warning device also includes a lower guide sleeve arranged on the inclined steel pile, the lower guide sleeve is close to the lower end of the inclined steel pile, and the warning steel bar passes through the lower guide sleeve.

4. The foundation pit retaining construction method using inclined pile support according to claim 3 is characterized in that: An extension steel bar is provided at the lower end of the warning steel bar, the extension steel bar is coaxial with the warning steel bar, the outer diameter of the extension steel bar is smaller than the outer diameter of the warning steel bar, the resistance piece is provided with a plug hole, the extension steel bar is inserted in the plug hole, and the resistance piece is against the lower end surface of the warning steel bar.

5. The foundation pit retaining construction method using inclined pile support according to claim 1 or 2 is characterized in that: The inclination angle of the cement soil mixing pile is 40-75 degrees.

6. The foundation pit retaining construction method using inclined pile support according to claim 5 is characterized in that: The inclination angle of the cement soil mixing pile is 60 degrees.

7. The foundation pit retaining construction method using inclined pile support according to claim 1 or 2 is characterized in that: The inclined steel piles are H-shaped steel or round steel pipes or square steel pipes or steel lattice columns.

8. The foundation pit retaining construction method using inclined pile support according to claim 1 is characterized in that: It includes foundation pit retaining piles distributed along the edge of the foundation pit, inclined piles located on the inner side of the foundation pit retaining piles and capping beams extending along the upper ends of the foundation pit retaining piles. The inclined piles include cement soil mixing piles arranged in the foundation pit soil layer on the inner side of the foundation pit retaining piles and inclined steel piles inserted in the cement soil mixing piles. The cement soil mixing piles are distributed obliquely, the upper ends of the cement soil mixing piles are close to the upper ends of the foundation pit retaining piles or intersect with the upper ends of the foundation pit retaining piles, the lower ends of the cement soil mixing piles are inclined toward the middle of the foundation pit, and the tops of the inclined steel piles are buried in the capping beam so that the upper ends of the foundation pit retaining piles and the upper ends of the inclined piles are connected as a whole through the capping beam.

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