Prestress jacking device in foundation pit and prestress applying method

Abstract

The invention discloses a prestress jacking device in a foundation pit and a prestress applying method. The prestress jacking device comprises a loading base (11) and two diagonal bracing mechanisms (12), each diagonal bracing mechanism is provided with a top bracing output end, the two diagonal bracing mechanisms are respectively an upper diagonal bracing mechanism (128) and a lower diagonal bracing mechanism (129), and the lower diagonal bracing mechanism obliquely downwards extends out of the top bracing output end to be supported at the position, close to the pit bottom, of the enclosure and applies top bracing prestress to the position, close to the pit bottom, of the enclosure; the upper inclined strut mechanism obliquely and upwards extends out of the top support output end to be supported on the upper portion of the enclosure close to the bottom support. The prestress applying method comprises the steps that after construction of the near-pit-bottom horizontal support is completed, the prestress jacking and supporting device (1) is installed on the basis of the near-pit-bottom horizontal support, installation is completed before subsequent digging operation of a lower layer, and then jacking and supporting prestress is applied to the enclosure structure (2) through the prestress jacking and supporting device. And the part, close to the pit bottom, of the enclosure can obtain the top bracing prestress at the first time.

Description

Technical Field

[0001] The invention relates to the technical field of foundation pit engineering, and in particular to a prestressed top support device in a foundation pit and a method for applying prestressed stress. Background Art

[0002] Excavation of foundation pits will cause settlement and displacement of surrounding strata, thus affecting the safety of nearby subway tunnels and buildings. The main reason is that excavation of foundation pits will cause displacement and deformation of surrounding soil. Therefore, it is necessary to build a retaining support system during the construction of foundation pits to ensure the safety of the surrounding environment.

[0003] The current problem is:

[0004] The process of excavating the foundation pit and constructing the lower-level foundation pit structure requires a relatively long construction period. Before the lower-level foundation pit structure is completed, it is impossible to apply top support prestressing to the retaining wall near the bottom of the pit. As a result, the retaining wall near the bottom of the pit may undergo displacement and deformation before the lower-level foundation pit structure is completed, which is not conducive to the construction quality of the entire foundation pit project. Summary of the invention

[0005] The object of the present invention is to provide a prestressed jacking support device and a method for applying prestress in a foundation pit, wherein the prestressed jacking support device and the method for applying prestress can apply jacking support prestress to the surrounding area near the bottom of the pit based on the horizontal support near the bottom of the pit, and the surrounding area near the bottom of the pit can obtain the applied jacking support prestress in the first time.

[0006] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0007] A prestressed top support device in a foundation pit, the prestressed top support device comprising a loading base and two diagonal support mechanisms;

[0008] The diagonal support mechanism has a top support output end, which can perform telescopic action and output a top support force;

[0009] The two diagonal bracing mechanisms serve as an upper diagonal bracing mechanism and a lower diagonal bracing mechanism respectively.

[0010] The upper oblique support mechanism is assembled on the loading base, and the lower oblique support mechanism is assembled on the loading base; the loading base is assembled on the horizontal support near the bottom of the pit;

[0011] The lower oblique support mechanism can extend obliquely downward to support the top support output end at the bottom of the enclosure near the pit, and apply top support prestress to the bottom of the enclosure near the pit;

[0012] The upper oblique support mechanism can extend obliquely upward to support the top support output end at the upper part of the enclosure near the bottom support.

[0013] Furthermore, the loading base is assembled on a horizontal support near the pit bottom, and its specific structural form is: the loading base has a snap-fit ​​groove, and the snap-fit ​​groove of the loading base is snap-fitted and assembled on the edge of the horizontal support near the pit bottom.

[0014] Furthermore, the diagonal support mechanism includes a top support telescopic rod and an angle adjustment telescopic rod;

[0015] One end of the top support telescopic rod serves as the main body end, and the other end of the top support telescopic rod serves as the top support output end;

[0016] The main body end of the top support telescopic rod is assembled on the loading base through an axle pin hinge mechanism, and the top support telescopic rod can swing up and down based on the loading base;

[0017] The angle-adjusting telescopic rod is assembled on the loading base, a hoop is assembled at the telescopic end of the angle-adjusting telescopic rod, the top-supporting telescopic rod is assembled in the hoop, and the top-supporting telescopic rod is assembled and connected with the telescopic end of the angle-adjusting telescopic rod through the hoop; the telescopic action of the angle-adjusting telescopic rod can drive the top-supporting telescopic rod to adjust the angle of the up and down swing;

[0018] The top support telescopic rod of the upper diagonal support mechanism faces an obliquely upward direction, and the top support telescopic rod of the lower diagonal support mechanism faces an obliquely downward direction.

[0019] Furthermore, the top support telescopic rod comprises a top support rod and a top support base;

[0020] The top support rod and the top support base are assembled together through a sleeve nesting mechanism, and a driving telescopic cylinder is arranged in the sleeve nesting mechanism. The driving telescopic cylinder is used to drive the top support rod to perform a telescopic action relative to the top support base.

[0021] Furthermore, the supporting telescopic rod is a hydraulic piston rod.

[0022] Furthermore, the prestressed top support device also includes a pulling rod; the pulling rod is arranged between the top support telescopic rod of the upper diagonal support mechanism and the top support telescopic rod of the lower diagonal support mechanism, and the pulling rod connects the two top support telescopic rods.

[0023] Furthermore, a top support end is provided on the top support output end of the diagonal support mechanism, and the top support end is a square type or a wide type.

[0024] Furthermore, a device assembly interval is left between the edge of the horizontal support near the pit bottom and the enclosure structure;

[0025] The prestressed jacking device also includes a transverse jacking device; the transverse jacking device is arranged at the loading base and located at the device assembly interval, and the transverse jacking device applies transverse jacking prestress to the enclosure structure based on the horizontal supporting structure.

[0026] Further, the lateral supporting device comprises a placement box and a lateral supporting telescopic cylinder;

[0027] The transverse supporting telescopic cylinder is placed in the placement box;

[0028] The placement box is provided with overlapping ends, and the overlapping ends of the placement box are used to overlap on both sides of the device assembly interval.

[0029] Furthermore, an inclinometer is provided in the retaining structure of the foundation pit.

[0030] Furthermore, the loading base is U-shaped.

[0031] Furthermore, the loading base is an embedded part.

[0032] A method for applying prestress to a retaining wall in a foundation pit, wherein the method for applying prestress adopts a prestressed top support device, and the prestressed top support device comprises a loading base and two diagonal support mechanisms;

[0033] The diagonal support mechanism has a top support output end, which can perform telescopic action and output a top support force;

[0034] The two diagonal bracing mechanisms serve as an upper diagonal bracing mechanism and a lower diagonal bracing mechanism respectively.

[0035] The upper diagonal bracing mechanism is assembled on the loading base, and the lower diagonal bracing mechanism is assembled on the loading base;

[0036] The method for applying prestress comprises:

[0037] S1, construct horizontal support near the bottom of the pit;

[0038] S2, installing the prestressed top support device based on the horizontal support near the bottom of the pit, and completing the installation and setting of the prestressed top support device before the subsequent lower level excavation operation;

[0039] The loading base is assembled on the horizontal support near the pit bottom, the lower oblique support mechanism extends obliquely downward to support the top support output end at the position of the enclosure near the pit bottom, and applies top support prestress to the position of the enclosure near the pit bottom;

[0040] The upper oblique support mechanism extends obliquely upwards and the top support output end is supported at the upper part of the enclosure near the bottom support;

[0041] S3, using prestressed top support device to apply top support prestress to the enclosure structure, including:

[0042] The inclined bracing mechanism in the prestressed top bracing device is used to apply inclined top bracing prestress to the enclosure structure:

[0043] The top support output end of the lower oblique support mechanism applies top support prestressing force to the surrounding area near the bottom of the pit obliquely downward;

[0044] Detect the deformation condition of the retaining wall near the bottom of the pit, and control the lower diagonal support mechanism to apply top support prestress to the retaining wall near the bottom of the pit according to the deformation condition of the retaining wall near the bottom of the pit.

[0045] Further,

[0046] A device assembly interval is left between the edge of the horizontal support near the pit bottom and the surrounding structure;

[0047] The prestressed supporting device further comprises a transverse supporting device; the transverse supporting device is arranged at the loading base and is located at the device assembly interval;

[0048] The edge of the horizontal support near the pit bottom is fixedly provided with a pier, the pier is located at the device assembly interval, and the pier forms a top support posture for the enclosure structure based on the edge of the horizontal support near the pit bottom;

[0049] The method of applying prestress to the enclosure structure by using the prestressed support device also includes:

[0050] A transverse top support device in the prestressed top support device is used to apply a transverse top support prestress to the enclosure structure: the transverse top support device applies a transverse top support prestress to the enclosure structure based on the horizontal support structure;

[0051] Detect the deformation of the enclosure structure, and according to the deformation of the enclosure structure, control the transverse top support device to apply top support prestress to the enclosure structure, so that the deformation of the enclosure structure meets the design standards;

[0052] Grouting material is poured into the position where the pier forms a top support posture to connect the pier with the surrounding structure.

[0053] Furthermore, for the horizontal support near the bottom of the pit, a corresponding external ring beam is provided on the enclosure structure;

[0054] The device assembly interval refers to the space between the edge of the horizontal support near the pit bottom and the external ring beam.

[0055] Furthermore, when constructing the horizontal support near the pit bottom, a wooden box is installed in the soil at the predetermined installation position of the prestressed top support device, and the wooden box is specifically installed below the horizontal support near the pit bottom.

[0056] Furthermore, after the construction of the lower level foundation pit structure is completed, the prestressed top support device is removed, or the prestressed top support device is retained and not removed.

[0057] Compared with the prior art, the prestressed top support device of the present invention has the following main beneficial effects:

[0058] After completing the construction of the horizontal support near the pit bottom, the prestressed jacking support device is immediately installed based on the horizontal support near the pit bottom, and the installation is completed before the subsequent lower-level excavation operation, and then the prestressed jacking support device is used to apply jacking prestress to the retaining structure; the jacking output end of the lower oblique support mechanism provided in the prestressed jacking support device can slant downward to support the retaining structure near the bottom of the pit, and can apply jacking prestress to the retaining structure near the bottom of the pit; in this way, the retaining structure near the bottom of the pit can obtain the application of jacking prestress in the first time, so that the displacement deformation of the retaining structure near the bottom of the pit can be timely controlled, thereby improving the overall engineering quality of the foundation pit project. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 It is a structural schematic diagram of a prestressed top support device according to Embodiment 1 of the present invention;

[0060] Figure 2 for Figure 1 A schematic diagram of the structure of the telescopic rod for adjusting the middle angle;

[0061] Figure 3 It is a schematic diagram of applying top support prestress to the enclosure structure by using a prestressed top support device in implementation mode 1;

[0062] Figure 4 It is a structural schematic diagram of a transverse supporting device in a prestressed supporting device of implementation mode 1;

[0063] Figure 5 This is a schematic diagram of arranging a wooden box at the edge of the horizontal supporting structure in Embodiment 1;

[0064] Figure 6 This is a schematic diagram of not removing the prestressed top support device after the lower level foundation pit structure is completed;

[0065] Figure 7 A schematic diagram of removing the prestressed top support device after the lower level foundation pit structure is completed;

[0066] Figure 8 It is a structural schematic diagram of a prestressed top support device according to Embodiment 2 of the present invention;

[0067] Fig. 9 It is a schematic diagram of applying top support prestress to the enclosure structure by using a prestressed top support device in implementation mode 2;

[0068] Fig.10 It is a schematic structural diagram of a prestressed supporting device according to Embodiment 3 of the present invention. DETAILED DESCRIPTION

[0069] First of all, in order to facilitate a clear and accurate description of the technical solution in the following text, the following definitions are made in advance:

[0070] Definition 1: The "current pit bottom" mentioned in this article refers to the pit bottom during the foundation pit construction excavation process. The "current pit bottom" is a dynamic concept. Wherever the foundation pit is excavated is the "current pit bottom".

[0071] Definition 2: The "designed pit bottom" mentioned in this article refers to the pit bottom designed for foundation pit engineering. The "designed pit bottom" is a static concept.

[0072] Definition 3: The "horizontal support near the pit bottom" mentioned in this article refers to the horizontal support structure that has been built in the foundation pit and is closest to the current pit bottom. The "horizontal support near the pit bottom" is a dynamic concept. For example, when the first layer of horizontal support structure is completed, the first layer of horizontal support structure is the horizontal support near the pit bottom. When the second layer of horizontal support structure is completed, the second layer of horizontal support structure is the horizontal support near the pit bottom, and the first layer of horizontal support structure is no longer the horizontal support near the pit bottom.

[0073] Definition 4: The "enclosure near the pit bottom" mentioned in this article refers to the part of the enclosure structure close to the current pit bottom. The "enclosure near the pit bottom" is a dynamic concept, which changes with the position of the current pit bottom. For example, when the "current pit bottom" is excavated to a depth of 1 meter, the part of the enclosure structure close to a depth of 1 meter is the "enclosure near the pit bottom".

[0074] Definition 5: The "upper part of the support near the bottom" mentioned in this article refers to the part of the support structure that is adjacent to the horizontal support near the bottom of the pit and is located above the horizontal support near the bottom of the pit. The "upper part of the support near the bottom" is a dynamic concept that changes with the change of the horizontal support near the bottom of the pit.

[0075] Definition 6: The "support system" mentioned in this article is a broad concept, which summarizes all forms of "support structures" and their combinations for the retaining structures in the foundation pit, such as "inclined upward support structure" and "horizontal support structure".

[0076] Definition 7: The "lower level foundation pit structure" mentioned in this article refers to the deeper foundation pit structure to be constructed in the next stage of the foundation pit construction process. The "lower level foundation pit structure" is a dynamic concept. For example, there are two layers of horizontal support structures designed in the foundation pit. When the first layer of horizontal support structure is completed, the second layer of horizontal support structure to be constructed is the lower level foundation pit structure. When the second layer of horizontal support structure is completed, the bottom structure of the foundation pit to be constructed is the lower level foundation pit structure.

[0077] Definition 8: The "lower level excavation" mentioned in this article refers to the process of excavation in the foundation pit before the next stage of the construction of a deeper foundation pit structure, so as to open up a construction space for the deeper foundation pit structure. The excavation process during this period is called "lower level excavation". For example, there are two layers of horizontal support structures in the foundation pit. After the construction of the first layer of horizontal support structures is completed, it is necessary to excavate downwards to open up a construction space for the second layer of horizontal support structures. The excavation process during this period is called lower level excavation.

[0078] The concept of the present invention is further described below with specific embodiments:

[0079] Implementation 1:

[0080] See also Figure 1 This embodiment 1 provides a prestressed support device in a foundation pit. The prestressed support device 1 mainly includes a loading base 11, a diagonal support mechanism 12 and a pulling rod 13.

[0081] The loading base 11 is in a horizontal "U" shape as a whole.

[0082] For the convenience of description,

[0083] The U-shaped inner recessed portion of the loading base 11 is called a clamping groove 111.

[0084] The upper surface of the loading base 11 is referred to as an upper seat surface 112.

[0085] The lower surface of the loading base 11 is referred to as the lower seat surface 113.

[0086] The outer bottom surface of the "U" shape of the loading base 11 is called the side seat surface 114.

[0087] The loading base 11 is used to be assembled with the horizontal support structure 3 (described in detail later).

[0088] It should be noted that the loading base 11 may also be an embedded part reserved on the ring beam.

[0089] The upper seat surface 112 and the lower seat surface 113 of the loading base 11 are both provided with diagonal support mechanisms 12 , that is, two diagonal support mechanisms 12 are provided.

[0090] For the convenience of description,

[0091] The diagonal support mechanism 12 disposed on the upper seat surface 112 is referred to as an upper diagonal support mechanism 128.

[0092] The diagonal support mechanism 12 disposed on the lower seat surface 113 is referred to as a lower diagonal support mechanism 129.

[0093] The upper diagonal bracing mechanism 128 and the lower diagonal bracing mechanism 129 have the same structural composition, but are arranged in different orientations.

[0094] In summary,

[0095] The diagonal bracing mechanism 12 is arranged based on the upper seat surface 112 or the lower seat surface 113, and has a supporting output end, which can perform telescopic motion relative to the body of the diagonal bracing mechanism 12 and output supporting force to the outside. In this way, the diagonal bracing mechanism 12 can apply supporting force to the outside (enclosing structure) based on the loading base 11, and the direction and angle of applying the supporting force can be adjusted.

[0096] Specifically,

[0097] The diagonal support mechanism 12 mainly includes a top support rod 121 , a top support base 122 and an angle adjustment telescopic rod 124 .

[0098] The supporting base 122 is assembled on the upper seat surface 112 or the lower seat surface 113 of the loading base 11 through an axle pin hinge mechanism, so that the supporting rod 121 to be mentioned later can swing up and down based on the upper seat surface 112 or the lower seat surface 113 of the loading base 11.

[0099] One end of the supporting rod 121 is used as an assembly end, and the other end is used as a supporting output end (that is, the supporting output end of the entire diagonal supporting mechanism 12); the assembly end of the supporting rod 121 is assembled with the supporting base 122, and a sleeve nesting assembly form is adopted at the assembly point of the two. Such a sleeve nesting assembly form can also be regarded as a sleeve nesting mechanism. In other words, the assembly end of the supporting rod 121 is assembled with the supporting base 122 through the sleeve nesting mechanism 123, so that the supporting rod 121 can perform telescopic action relative to the supporting base 122 based on the sleeve nesting mechanism 123.

[0100] In addition, a driving telescopic cylinder of the prior art (which can be a hydraulic cylinder or an electric cylinder) is also provided in the sleeve nesting mechanism 123. The main body (cylinder body) of the driving telescopic cylinder is fixedly connected to the top support base 122, and the telescopic end (cylinder head) of the driving telescopic cylinder is fixedly connected to the top support rod 121. In this way, the driving telescopic cylinder can drive the top support rod 121 to perform a telescopic action relative to the top support base 122.

[0101] It should be noted that the rod body formed by the aforementioned supporting rod 121, supporting base 122, sleeve nesting mechanism 123, driving telescopic cylinder, etc. can be summarized as a supporting telescopic rod, which can perform telescopic action and output supporting force to the outside. One end of the supporting telescopic rod serves as the main body end (equivalent to the supporting base 122), and the other end of the supporting telescopic rod serves as the supporting output end (equivalent to the supporting output end of the supporting rod 121).

[0102] The main body end of the supporting telescopic rod is assembled on the upper seat surface 112 or the lower seat surface 113 of the loading base 11 through an axle pin hinge mechanism, so that the entire supporting telescopic rod can swing up and down based on the upper seat surface 112 or the lower seat surface 113 of the loading base 11.

[0103] The supporting rod 121 mentioned in the following text can be generally understood as the rod body of the supporting telescopic rod.

[0104] In addition, a supporting end 125 is provided at the supporting output end of the supporting rod 121 . The supporting end 125 is in a square shape and is used to directly lean against the enclosure structure 2 .

[0105] See also Figure 1 and Figure 2 In order to adjust the swing angle of the top support rod 121 , an angle adjustment telescopic rod 124 is also provided for the top support rod 121 .

[0106] One end of the body of the angle-adjusting telescopic rod 124 is assembled and connected based on the upper seat surface 112 or the lower seat surface 113 of the loading base 11, and a hoop 1241 is assembled at the telescopic end of the angle-adjusting telescopic rod 124 through an axle pin hinge mechanism (not shown in the figure), and the hoop 1241 can rotate based on the telescopic end of the angle-adjusting telescopic rod 124. The top support rod 121 is assembled in the hoop 1241, that is, the top support rod 121 is assembled and connected with the telescopic end of the angle-adjusting telescopic rod 124 through the hoop 1241, and the top support rod 121 can slide in the hoop 1241. In this way, the telescopic action of the angle-adjusting telescopic rod 124 can drive the top support rod 121 to adjust the angle of the up and down swing.

[0107] It should be noted that the angle-adjustable telescopic rod 124 may be a hydraulic cylinder telescopic rod or an electric cylinder telescopic rod.

[0108] At this point, the supporting rod 121 can output a supporting force to the outside based on the upper seat surface 112 or the lower seat surface 113 of the loading base 11, and can also adjust the up and down swing angle.

[0109] The supporting output end of the supporting rod 121 of the upper oblique supporting mechanism 128 arranged on the upper seat surface 112 of the loading base 11 can support in an oblique upward direction, while the supporting output end of the supporting rod 121 of the lower oblique supporting mechanism 129 arranged on the lower seat surface 113 of the loading base 11 can support in an oblique downward direction.

[0110] The prestressed top support device of this embodiment is applied to the joint between the enclosure structure 2 and the horizontal support structure 3.

[0111] The foundation pit engineering structure involved in this implementation mode is first introduced below.

[0112] Those skilled in the art can understand that the overall engineering structure of the foundation pit mainly includes the enclosure structure 2 and the enclosure support system, and its specific structure is set as follows:

[0113] The retaining structure 2 is constructed around the foundation pit, and the retaining support system is usually arranged inside the foundation pit to support the retaining structure 2.

[0114] In this embodiment, the enclosure support system is mainly composed of several layers of horizontal support structures 3. The several layers of horizontal support structures 3 are arranged on the inner side of the foundation pit, and the enclosure structure 2 is supported by these horizontal support structures 3. In this embodiment, the number of horizontal support structures 3 is three.

[0115] For each layer of horizontal support structure 3, a corresponding external ring beam 5 is arranged on the enclosure structure 2. For each layer of horizontal support structure 3, a certain spacing distance is left between its edge and the external ring beam 5 on the enclosure structure 2, that is, the two are separated, and the separated part is specially used for setting the prestressing mechanism.

[0116] The edge of the horizontal support structure 3 is connected to the external ring beam 5 through a prestressed mechanism, and then connected to the enclosure structure 2 through the external ring beam 5, thereby forming support for the enclosure structure 2.

[0117] For the convenience of subsequent description, the spaced apart portion is referred to as a device assembly space.

[0118] It should be noted that, in other embodiments, if the external ring beam 5 is not provided on the enclosure structure 2 , the device assembly interval refers to the space between the edge of the horizontal support structure 3 and the enclosure structure 2 .

[0119] A large number of buttresses 7 are arranged at the assembly interval of the device, and these buttresses 7 are arranged at the edge of the horizontal supporting structure 3 by “casting together with the edge of the horizontal supporting structure 3”.

[0120] It should be noted that a pre-buried steel plate is embedded between the pier 7 and the retaining structure 2 or the external ring beam 5, which is only used to separate the connection between the pier 7 and the retaining structure 2 or the external ring beam 5, so as to form a gap during prestressed loading, and then grouting material is used to fill the gap tightly.

[0121] These numerous piers 7 are evenly and discretely arranged around the edge of the horizontal support structure 3, and these numerous piers 7 are spaced apart from the numerous prestressed supporting devices 1 to be mentioned later; each pier 7 forms a supporting posture for the external ring beam 5 based on the edge of the horizontal support structure 3, which essentially forms a supporting posture for the enclosing structure 2 through the external ring beam 5.

[0122] It should be noted that at this time, the buttress 7 only forms a "top supporting posture", and it is not in contact with the external ring beam 5, but the two are very close to each other, thus forming a "top supporting posture".

[0123] A stiffening plate 4 and a built-in ring beam 6 are provided at the edge of the horizontal support structure 3 to improve the structural strength of the edge of the horizontal support structure 3. It should be noted that the stiffening plate 4 can be replaced with a support arranged in an eight-shaped shape.

[0124] In this embodiment, the enclosure structure 2 is a continuous wall enclosure structure 21 .

[0125] In addition, in order to conveniently detect the displacement and deformation of the enclosure structure 2 and obtain corresponding data, in this embodiment, a prior art inclinometer 8 is pre-buried inside the enclosure structure 2, through which the displacement and deformation related data of the enclosure structure 2 can be detected and obtained.

[0126] Those skilled in the art can understand that the above-mentioned foundation pit engineering structure is a structure of the prior art.

[0127] See also Figure 3 The specific installation and use method of the prestressed support device 1 is as follows:

[0128] The loading base 11 is assembled at the edge of the horizontal support structure 3, so that the clamping groove 111 of the loading base 11 is clamped at the edge of the horizontal support structure 3. For the upper oblique support mechanism 128 and the lower oblique support mechanism 129, the angle adjustment telescopic rod 124 is controlled to be extended and retracted to adjust the angle of the top support rod 121. The top support output ends of the top support rods 121 of the two oblique support mechanisms 12 are inclined toward the enclosure structure 2, the top support rod 121 of the upper oblique support mechanism 128 is inclined upward, and the top support rod 121 of the lower oblique support mechanism 129 is inclined downward, and then the driving telescopic cylinder in the sleeve nesting mechanism 123 is controlled to drive the top support rod 121 to extend, so that The supporting end 125 at the supporting output end of the supporting rod 121 is supported on the enclosure structure 2, and the supporting output end of the supporting rod 121 of the lower diagonal supporting mechanism 129 is supported on the enclosure structure 2 at an angle downward, thereby applying supporting prestress to the enclosure structure 2, and the supporting output end of the supporting rod 121 of the upper diagonal supporting mechanism 128 is supported on the enclosure structure 2 at an angle upward, thereby applying a supporting force downward on the edge of the horizontal supporting structure 3 based on the enclosure structure 2 to offset the reaction force generated by the supporting rod 121 of the lower diagonal supporting mechanism 129 on the horizontal supporting structure 3, thereby preventing the edge of the horizontal supporting structure 3 from deforming.

[0129] The greatest significance of the prestressed top support device 1 of this embodiment is that it is applied to the horizontal support near the pit bottom, and based on the horizontal support near the pit bottom, top support prestress is applied to the surrounding area near the pit bottom.

[0130] Specifically,

[0131] A large number of prestressed top support devices 1 are set at the device assembly interval between the horizontal support near the pit bottom and the surrounding structure 2, and are evenly and discretely arranged around the edge of the horizontal support near the pit bottom.

[0132] For each prestressed jacking support device 1, the loading base 11 is snap-fitted and assembled on the edge of the horizontal support near the bottom of the pit, and the lower oblique support mechanism 129 is adjusted so that the jacking output end of its jacking support rod 121 is slanted downwardly supported at the position of the enclosure near the bottom of the pit, thereby being able to apply jacking support prestress to the position of the enclosure near the bottom of the pit; the upper oblique support mechanism 128 is adjusted so that the jacking output end of its jacking support rod 121 is slanted upwardly supported at the upper part of the enclosure near the bottom support, thereby being able to offset the reaction force generated by the jacking support rod 121 of the lower oblique support mechanism 129 on the horizontal support near the bottom of the pit, thereby preventing the edge of the horizontal support near the bottom of the pit from deformation.

[0133] The prestressed top support device 1 arranged at the horizontal support near the bottom of the pit can apply top support prestress to the surrounding area near the bottom of the pit before the lower level excavation operation, so that the displacement and deformation of the surrounding area near the bottom of the pit can be controlled in time at the first time, thereby improving the overall engineering quality of the foundation pit project.

[0134] In addition, for each prestressed supporting device 1, a pulling rod 13 is arranged between the upper and lower supporting rods 121, and the pulling rod 13 connects the two supporting rods 121, thereby preventing the supporting output end of the supporting rod 121 from slipping on the enclosure structure 2 and falling off.

[0135] See also Figure 4 The prestressed jacking device of this embodiment also includes a transverse jacking device 14, which is composed of a placement box 141 and a transverse jacking telescopic cylinder 142.

[0136] The transverse supporting telescopic cylinder 142 may be a hydraulic cylinder or an electric cylinder.

[0137] The transverse supporting telescopic cylinder 142 is placed in a placement box 141 , and four overlapping ends 1411 are symmetrically arranged around the periphery of the placement box 141 .

[0138] The transverse supporting device 14 is integrally arranged on the side seat surface 114 of the loading base 11 .

[0139] When the prestressed jacking device 1 is installed at the junction of the enclosure structure 2 and the horizontal support structure 3, the transverse jacking device 14 is located as a whole at the device assembly interval, and the overlapping ends 1411 of the placement box 141 are overlapped on both sides of the device assembly interval, namely, on the upper seat surface 112 of the loading base 11, and on the external ring beam 5, so that the transverse jacking device 14 can be stably placed in the device assembly interval.

[0140] The transverse supporting telescopic cylinder 142 in the transverse supporting device 14 is in a horizontal state, and one end of its main body (cylinder body) is against the side seat surface 114 of the loading base 11 through the wall panel of the housing box 141 (if there is no wall panel, it will be directly against it), and the telescopic end (cylinder head) of the transverse supporting telescopic cylinder 142 is supported on the external ring beam 5, that is, it is supported on the enclosure structure 2 through the external ring beam 5, so that, based on the edge of the horizontal supporting structure 3, transverse supporting prestress is applied to the enclosure structure 2 through the external ring beam 5.

[0141] It should be noted that the transverse supporting device 14 is not essential and can be provided as required.

[0142] This embodiment also provides a method for applying prestress, which uses the above-mentioned prestressed top support device to apply top support prestress to the retaining structure 2, especially to apply top support prestress to the retaining structure near the bottom of the pit.

[0143] The method for applying prestress comprises steps S1 to S3:

[0144] S1, construct a horizontal support structure 3 (horizontal support near the bottom of the pit) at the foundation pit construction location;

[0145] The constructed horizontal support structure 3 is as described above and will not be described in detail here.

[0146] See also Figure 5 It should be noted that when constructing the horizontal support structure 3, a wooden box 9 is installed in the soil at the predetermined installation position of the prestressed top support device 1. The wooden box 9 is specifically installed below the horizontal support near the bottom of the pit.

[0147] The purpose of setting the wooden box 9 is that when installing the loading base 11, there is still soil under the horizontal support structure 3, and there is no installation space at this time. During installation, the wooden box 9 can be taken out to reserve installation space for subsequent installation.

[0148] S2, after completing the construction of the horizontal support near the pit bottom in step S1, immediately start installing the previously mentioned prestressed top support device based on the horizontal support near the pit bottom, and complete the installation and setting before the subsequent lower level excavation operation.

[0149] The specific installation structure of the prestressed top support device has been described before and will not be repeated here.

[0150] Just one extra note:

[0151] When the loading base 11 is clamped to the edge of the horizontal support structure 3, the lower seat surface 113 of the loading base 11 is placed in the wooden box 9, so that the clamping point between the loading base 11 and the horizontal support structure 3 can be prevented from being contaminated by soil. After the lower level excavation operation, the wooden box 9 is removed.

[0152] S3, before the subsequent lower level excavation operation, the prestressed top support device 1 is used to apply top support prestress to the enclosure structure 2.

[0153] The step S3 specifically includes S31 to S32.

[0154] S31, using the transverse supporting device 14 in the prestressed supporting device 1 to apply transverse supporting prestress to the enclosure structure 2.

[0155] Specifically,

[0156] The transverse supporting device 14 applies transverse supporting prestress to the enclosure structure 2 based on the horizontal supporting structure 3; controls the extension and retraction of the telescopic end of the transverse supporting telescopic cylinder 142 in the transverse supporting device 14, so that the telescopic end of the transverse supporting telescopic cylinder 142, as the supporting output end of the entire transverse supporting device 14, extends laterally and supports on the external ring beam 5, and the supporting prestress applied by the transverse supporting device 14 acts on the enclosure structure 2 through the external ring beam 5.

[0157] The deformation condition (deformation data) of the retaining structure 2 is detected by the detection means of the existing technology. According to the deformation condition of the retaining structure 2 and in accordance with the design standards, the transverse supporting device 14 is controlled to apply appropriate supporting prestress to the retaining structure 2 so that the deformation condition of the retaining structure 2 meets the design standards.

[0158] Then, grouting material is poured at the position where a "supporting posture" is formed between the pier 7 and the external ring beam 5. After the grouting material is completely solidified, the pier 7 and the external ring beam 5 are truly connected together, and the pier 7 is truly based on the horizontal support structure 3 and applies transverse supporting prestress to the retaining structure 2 through the external ring beam 5.

[0159] Finally, the entire transverse supporting device 14 is disassembled, and the pier 7 is completely used to exert the role of applying transverse supporting prestress.

[0160] It should be noted that, in other embodiments, if the external ring beam 5 is not provided on the enclosure structure 2 , the supporting output end of the transverse supporting device 14 and the pier 7 are directly supported on the enclosure structure 2 .

[0161] S32, using the oblique support mechanism 12 in the prestressed support device 1 to apply oblique support prestress to the enclosure structure 2.

[0162] Specifically,

[0163] The top support output end of the lower oblique support mechanism 129 (that is, the top support output end of the top support rod 121) is adjusted to an azimuth angle obliquely downward toward the enclosure structure 2 (the enclosure near the bottom of the pit).

[0164] Then, the top support rod 121 is controlled and adjusted to extend and retract, so that the top support output end of the top support rod 121 extends obliquely downward and the top support end 125 on it abuts against the top support on the enclosure structure 2 (the enclosure near the bottom of the pit).

[0165] The top support prestress applied by the lower diagonal support mechanism 129 acts on the enclosure structure 2 (the enclosure near the bottom of the pit).

[0166] The existing detection means are used to detect the deformation condition (deformation data) of the retaining structure 2 (the retaining part near the bottom of the pit). According to the deformation condition of the retaining structure 2 (the retaining part near the bottom of the pit) and in accordance with the design standards, the lower diagonal bracing mechanism 129 is controlled to apply appropriate top bracing prestress to the retaining structure 2 (the retaining part near the bottom of the pit) so that the deformation condition of the retaining structure 2 meets the design standards.

[0167] The top support output end of the upper oblique support mechanism 128 (that is, the top support output end of the top support rod 121) is adjusted to an angle of obliquely upward toward the enclosure structure 2 (the upper part of the enclosure near the bottom support),

[0168] Then, the top support rod 121 is controlled and adjusted to extend and retract, so that the top support output end of the top support rod 121 extends obliquely upward and the top support end 125 on it abuts against the top support on the enclosure structure 2 (the upper part of the enclosure near the bottom support).

[0169] In this way, the reaction force generated by the lower diagonal support mechanism 129 on the horizontal support structure 3 can be offset, thereby preventing the edge of the horizontal support structure 3 from being deformed.

[0170] After the prestressing method is implemented, the subsequent lower level excavation work can be started.

[0171] It should be noted that, in this embodiment, a large number of inclinometers 8 (existing technology) are provided inside the retaining structure 2, and the deformation condition of the retaining structure 2, including the deformation condition of the retaining structure near the bottom of the pit, can be detected by these inclinometers 8.

[0172] It should be noted that the prestressed support device and the method for applying prestress in this embodiment are not only implemented for one-layer horizontal support structure 3, but can also be implemented for multiple-layer horizontal support structures 3.

[0173] Whenever a layer of horizontal support near the pit bottom is completed, the above-mentioned prestressed top support device and prestressing method can be used to apply top support prestress to the retaining structure 2 based on the horizontal support near the pit bottom that has just been constructed, thereby ensuring that the retaining structure 2, especially the retaining part near the pit bottom, can receive timely top support prestressing.

[0174] It should be noted that after the lower level foundation pit structure is constructed, the prestressed top support device 1 may be retained without removal. Figure 6 As shown, the prestressed top support device 1 can also be removed. Figure 7 shown.

[0175] It should be noted that the prestressed top support device can be used in the entire enclosure structure or in a partial enclosure structure.

[0176] It should be noted that the upper seat surface 112 and the lower seat surface 113 of the loading base 11 both extend a long distance away from the enclosure structure, and the position where the diagonal support mechanism 12 is assembled on the loading base 11 should be away from the enclosure structure, which is conducive to adapting to smaller device assembly intervals.

[0177] The main advantages of the prestressed top support device and the prestressing method of this embodiment are:

[0178] 1) After the construction of the horizontal support near the pit bottom is completed, the prestressed top support device 1 is immediately installed based on the horizontal support near the pit bottom, and the installation is completed before the subsequent lower level excavation operation, and then the prestressed top support device 1 is used to apply top support prestress to the enclosure structure 2;

[0179] The supporting output end of the lower oblique supporting mechanism 129 provided in the prestressed supporting device 1 can support obliquely downward at the position of the enclosure near the bottom of the pit, and can apply supporting prestress to the position of the enclosure near the bottom of the pit;

[0180] In this way, the top support prestress can be applied to the part of the retaining wall near the bottom of the pit in the first place, so that the displacement and deformation of the part of the retaining wall near the bottom of the pit can be controlled in time, thereby improving the overall engineering quality of the foundation pit project.

[0181] 2) The supporting output end of the upper diagonal supporting mechanism 128 provided in the prestressed supporting device 1 can be supported obliquely upward at the upper part of the support near the bottom of the enclosure. The upper diagonal supporting mechanism 128 can apply an oblique downward supporting force to the edge of the horizontal support near the bottom of the pit based on the enclosure structure 2 to offset the reaction force of the lower diagonal supporting mechanism 129, thereby preventing the edge of the horizontal support near the bottom of the pit from being deformed.

[0182] 3) The prestressed supporting device is also provided with a transverse supporting device 14, which can apply transverse supporting prestress to the enclosure structure 2 based on the horizontal supporting structure 3, so that the displacement deformation of the enclosure structure portion corresponding to the horizontal supporting structure 3 can be timely controlled.

[0183] Implementation 2:

[0184] See also Figures 8 to 9 , this embodiment 2 also provides a prestressed support device and a method for applying prestress, and the overall concept of the prestressed support device and the method for applying prestress is basically consistent with that of embodiment 1. The main differences between the prestressed support device and the method for applying prestress in this embodiment 2 and embodiment 1 are:

[0185] The retaining structure 2 of the foundation pit project is a pile retaining structure 22.

[0186] In order to adapt to this situation, the supporting end 125 provided on the supporting output end of the supporting rod 121 is of a wide type, specifically, a T-type.

[0187] Implementation 3:

[0188] See also Fig.10 , this embodiment 3 also provides a prestressed support device and a method for applying prestress, and the overall concept of the prestressed support device and the method for applying prestress is basically consistent with that of embodiment 1.

[0189] The main differences between the prestressed top support device and the prestressing method of the second embodiment and those of the first embodiment are:

[0190] A hydraulic piston rod 127 is used to replace the combination of the supporting rod 121, the supporting base 122, the sleeve nesting mechanism 123, the driving telescopic cylinder, etc., as another form of supporting telescopic rod. The end where the outer arm of the hydraulic piston rod 127 is located is equivalent to the main body end of the supporting telescopic rod, and the end where the inner arm of the hydraulic piston rod 127 is located is equivalent to the supporting output end of the supporting telescopic rod. In this way, the effect achieved is consistent with that of embodiment 1.

[0191] The above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A prestressed top support device in a foundation pit, characterized in that: The prestressed supporting device (1) comprises a loading base (11) and two diagonal supporting mechanisms (12); The diagonal support mechanism (12) has a support output end, which can perform telescopic action and output a support force; The two diagonal bracing mechanisms (12) serve as an upper diagonal bracing mechanism (128) and a lower diagonal bracing mechanism (129), respectively. The upper oblique support mechanism (128) is mounted on the loading base (11), and the lower oblique support mechanism (129) is mounted on the loading base (11); the loading base (11) is mounted on a horizontal support near the bottom of the pit; The lower oblique support mechanism (129) can extend obliquely downward to support the top support output end at the bottom of the enclosure near the pit, and apply top support prestress to the bottom of the enclosure near the pit; The upper oblique support mechanism (128) can extend obliquely upward to support the top support output end at the upper part of the enclosure near the bottom support.

2. The prestressed top support device in the foundation pit according to claim 1, characterized in that: The loading base (11) is assembled on a horizontal support near the pit bottom, and its specific structural form is: the loading base (11) has a clamping groove (111), and the clamping groove (111) of the loading base (11) is clamped and assembled on the edge of the horizontal support near the pit bottom.

3. The prestressed top support device in the foundation pit according to claim 1 is characterized in that: The diagonal support mechanism (12) comprises a top support telescopic rod and an angle adjustment telescopic rod (124); One end of the top support telescopic rod serves as the main body end, and the other end of the top support telescopic rod serves as the top support output end; The main body end of the supporting telescopic rod is assembled on the loading base (11) through an axle pin hinge mechanism, and the supporting telescopic rod can swing up and down based on the loading base (11); The angle-adjusting telescopic rod (124) is assembled based on the loading base (11); a hoop (1241) is assembled at the telescopic end of the angle-adjusting telescopic rod (124); the top-supporting telescopic rod is assembled in the hoop (1241); the top-supporting telescopic rod is assembled and connected with the telescopic end of the angle-adjusting telescopic rod (124) through the hoop (1241); the telescopic action of the angle-adjusting telescopic rod (124) can drive the top-supporting telescopic rod to adjust the angle of up and down swinging; The top support telescopic rod of the upper diagonal support mechanism (128) faces in an obliquely upward direction, and the top support telescopic rod of the lower diagonal support mechanism (129) faces in an obliquely downward direction.

4. The prestressed top support device in the foundation pit according to claim 3 is characterized in that: The top support telescopic rod comprises a top support rod (121) and a top support base (122); The supporting rod (121) and the supporting base (122) are assembled together via a sleeve nesting mechanism (123), wherein a driving telescopic cylinder is arranged in the sleeve nesting mechanism (123), and the driving telescopic cylinder is used to drive the supporting rod (121) to perform a telescopic action relative to the supporting base (122).

5. The prestressed top support device in the foundation pit according to claim 3 is characterized in that: The supporting telescopic rod is a hydraulic piston rod (127).

6. The prestressed top support device in the foundation pit according to claim 3, characterized in that: The prestressed support device (1) further comprises a pulling rod (13); the pulling rod (13) is arranged between the support telescopic rod of the upper diagonal support mechanism (128) and the support telescopic rod of the lower diagonal support mechanism (129); the pulling rod (13) connects the two support telescopic rods.

7. The prestressed top support device in the foundation pit according to claim 1, characterized in that: A top support end (125) is provided on the top support output end of the diagonal support mechanism (12), and the top support end (125) is square-shaped or wide-width.

8. The prestressed top support device in the foundation pit according to claim 1, characterized in that: A device assembly interval is left between the edge of the horizontal support near the pit bottom and the enclosure structure (2); The prestressed supporting device (1) further comprises a transverse supporting device (14); the transverse supporting device (14) is arranged at the loading base (11) and is located at the device assembly interval, and the transverse supporting device (14) applies transverse supporting prestress to the enclosure structure (2) based on the horizontal supporting structure (3).

9. The prestressed top support device in the foundation pit according to claim 8, characterized in that: The transverse supporting device (14) comprises a placement box (141) and a transverse supporting telescopic cylinder (142); The transverse supporting telescopic cylinder (142) is arranged in the arrangement box (141); The placement box (141) is provided with an overlapping end (1411), and the overlapping end (1411) of the placement box (141) is used to overlap on both sides of the device assembly interval.

10. The prestressed top support device in the foundation pit according to claim 1, characterized in that: An inclinometer (8) is arranged inside the foundation pit enclosure structure (2).

11. The prestressed top support device in the foundation pit according to claim 1, characterized in that: The loading base (11) is U-shaped.

12. The prestressed top support device in the foundation pit according to claim 1, characterized in that: The loading base (11) is an embedded part.

13. A method for applying prestress to the enclosure in a foundation pit, characterized in that: The method for applying prestress adopts a prestress support device (1), and the prestress support device (1) comprises a loading base (11) and two diagonal support mechanisms (12); The diagonal support mechanism (12) has a support output end, which can perform telescopic action and output a support force; The two diagonal bracing mechanisms (12) serve as an upper diagonal bracing mechanism (128) and a lower diagonal bracing mechanism (129), respectively. The upper diagonal bracing mechanism (128) is assembled on the loading base (11), and the lower diagonal bracing mechanism (129) is assembled on the loading base (11); The method for applying prestress comprises: S1, construct horizontal support near the bottom of the pit; S2, installing the prestressed top support device (1) based on the horizontal support near the bottom of the pit, and completing the installation and setting of the prestressed top support device (1) before the subsequent earth-moving operation of the lower layer; The loading base (11) is mounted on a horizontal support near the pit bottom, and the lower oblique support mechanism (129) extends obliquely downward to support the top support output end at the position of the enclosure near the pit bottom, and applies top support prestress to the position of the enclosure near the pit bottom; The upper oblique support mechanism (128) extends obliquely upwards and the top support output end is supported at the upper part of the enclosure near the bottom support; S3, applying a prestressing force to the enclosure structure (2) by using a prestressing force supporting device (1), comprising: The oblique support mechanism (12) in the prestressed support device (1) is used to apply oblique support prestress to the enclosure structure (2): The top support output end of the lower oblique support mechanism (129) applies top support prestressing force to the surrounding area near the bottom of the pit obliquely downward; The deformation condition of the enclosure near the pit bottom is detected, and according to the deformation condition of the enclosure near the pit bottom, the lower diagonal support mechanism (129) is controlled to apply top support prestress to the enclosure near the pit bottom.

14. The method for applying prestress to the enclosure in the foundation pit according to claim 13, characterized in that: A device assembly interval is left between the edge of the horizontal support near the pit bottom and the enclosure structure (2); The prestressed supporting device (1) further comprises a transverse supporting device (14); the transverse supporting device (14) is arranged on the loading base (11) and is located at the device assembly interval; A buttress (7) is fixedly provided on the edge of the horizontal support near the pit bottom, and the buttress (7) is located at the device assembly interval. The buttress (7) forms a supporting posture for the enclosure structure (2) based on the edge of the horizontal support near the pit bottom; The method of applying prestressed top support device (1) to the enclosure structure (2) includes: A transverse supporting device (14) in the prestressed supporting device (1) is used to apply transverse supporting prestress to the enclosure structure (2): the transverse supporting device (14) applies transverse supporting prestress to the enclosure structure (2) based on the horizontal supporting structure (3); Detecting the deformation condition of the enclosure structure (2), and controlling the transverse supporting device (14) to apply supporting prestress to the enclosure structure (2) according to the deformation condition of the enclosure structure (2), so that the deformation condition of the enclosure structure (2) meets the design standard; Grouting material is poured into the position where the buttress (7) forms a supporting posture, so that the buttress (7) and the surrounding structure (2) are connected together.

15. The method for applying prestress to the enclosure in the foundation pit according to claim 14, characterized in that: For the horizontal support near the pit bottom, a corresponding external ring beam (5) is arranged on the enclosure structure (2); The device assembly interval refers to the space between the edge of the horizontal support near the pit bottom and the external ring beam (5).

16. The method for applying prestress to the enclosure in the foundation pit according to claim 13, characterized in that: When constructing the horizontal support near the pit bottom, a wooden box (9) is installed in the soil at the predetermined installation location of the prestressed top support device (1), and the wooden box (9) is specifically installed below the horizontal support near the pit bottom.

17. The method for applying prestress to the enclosure in the foundation pit according to claim 13, characterized in that: After the lower level foundation pit structure is constructed, the prestressed top support device (1) is removed, or the prestressed top support device (1) is retained and not removed.

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