Steel caisson vertical continuous pressing relay device and construction method thereof

Abstract

The application provides a steel sinking well vertical continuous pressing relay device and a construction method thereof. The steel sinking well vertical continuous pressing relay device and the frictional resistance of the previously lowered steel sinking well provide the reaction force for the next stage steel sinking well to be pressed down. Thus, the longitudinal depth of the steel sinking well can be continuously developed, the problem of insufficient reaction force for the steel sinking well to be pressed down and the problem of instability of the well wall under the action of large load are solved, and the depth of the steel sinking well to be pressed down and the engineering safety are ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of underground engineering construction, and particularly relates to a steel caisson vertical continuous pressing relay device and a construction method thereof. BACKGROUND

[0002] With the development of urban construction, the existing pipe network is dense in the central city area, and the protection and avoidance of adjacent buildings bring new challenges to the construction of new work wells and pipe network projects in the central city area. The traditional open-cut enclosure and conventional concrete caisson, bored pile and diaphragm wall processes are restricted by the large occupation of land and the great influence on the surrounding environment during construction, which restricts the construction of work wells in the central city area. Therefore, it is urgent to develop a work well rapid construction method with small construction occupation, short cycle, low cost, low excavation risk and small influence on the surrounding environment, to solve the contradiction between the increasing demand for work wells and the complex urban environment.

[0003] In view of the disadvantages and deficiencies of the traditional enclosure and caisson method, the single-wall pressing type prefabricated steel caisson construction method is developed by the skilled person in the art, and is applied in the present construction. The process mainly uses a pressure system composed of pressing steel beams, anchor cables, ground beams and through-hole jacks to press the caisson into the soil by providing a downward pressure through the through-hole jacks, and fills the caisson bottom with concrete after sinking in place. On the one hand, the counterforce pressing system can guide the sinking and eliminate the adverse effects of the soil layer; on the other hand, the thin-wall pressing type prefabricated steel caisson has smaller soil squeezing effect and frictional resistance than the concrete caisson, and can realize excavation and soil removal after the well shaft is pressed into place, avoiding the phenomenon of blade foot emptying, so that the caisson can maintain a high soil plug while still having sufficient sinking coefficient, with small influence on the surrounding foundation and adjacent buildings, realizing low-impact and energy-efficient construction.

[0004] Although the single-wall pressing type steel caisson has good advantages, however, with the application of the steel caisson in the engineering site, it is found that the sinking resistance of the steel caisson increases greatly with the increase of the depth of the steel caisson. For example, the steel caisson steel beam counterforce records of three projects are as follows:

[0005]

[0006] Through the on-site steel caisson pressing reaction force, it is known that with the increase of the depth, the friction resistance of the lower soil layer gradually increases, and the pressing reaction force required by the steel caisson greatly increases (more than several times the depth), when the working well depth exceeds 18m, the pressing reaction force of the steel caisson exceeds 1000t. If the conventional (patent 202011437083.2) pressing steel caisson only sets the counterweight and anchor pile method on the ground, the following problems will be faced: ① The counterweight ring beam section required by the upper thousand tons and above pressing force needs to be greatly increased, and the anchor pile length also needs to be greatly increased. Since the working well site in the city is generally small, the demand for such a large counterweight often cannot meet the requirements of the counterweight ring beam section and anchor pile construction. ② If the single-wall steel caisson is pressed once at a large depth, with the increase of the depth-diameter ratio H / D, under the action of the large-tonnage pressing single-point concentrated force at the pressing point, the single thin-wall well wall is prone to local instability and buckling, which adversely affects the stress of the steel caisson structure.

[0007] The single-wall pressing steel caisson relies on the ground to provide the pressing reaction force, and there is a problem of insufficient pressing reaction force and well wall instability. The technical personnel in the field have been looking for a solution. SUMMARY

[0008] The purpose of the present application is to provide a steel caisson vertical continuous pressing relay device and its construction method, which can solve the problem of insufficient pressing reaction force and well wall instability of the single-wall pressing steel caisson relying on the ground to provide the pressing reaction force.

[0009] To solve the above technical problems, the present application provides a steel caisson vertical continuous pressing relay device, which comprises:

[0010] The first-stage steel caisson comprises a plurality of first-stage steel caisson segments, and all the first-stage steel caisson segments are vertically assembled to form the first-stage steel caisson.

[0011] The nth-stage steel caisson is arranged inside the (n-1)th-stage steel caisson, and comprises a plurality of nth-stage steel caisson segments, all of which are vertically spliced to form the nth-stage steel caisson; wherein the diameter of the (n-1)th-stage steel caisson is 200m-300m larger than that of the nth-stage steel caisson; n=H / h, n is the number of steel caisson stages and the number of steel caissons, h is the single pressing depth, and the value range is 14-16m; H is the total sinking height of the steel caisson, and n is an integer greater than or equal to 2;

[0012] The counterweight locking member comprises a counterweight ring beam, a plurality of pre-buried steel embedded panels arranged inside the counterweight ring beam, and a plurality of connecting steel plates, the counterweight ring beam is arranged outside the first-stage steel caisson, one end of every three connecting steel plates is vertically fixed on the adjacent pre-buried steel embedded panel, and the other end is vertically fixed on the well wall of the first-stage steel caisson;

[0013] n-1 steel caisson gap closure members, comprising: a plurality of gap grouting pipes and a capping beam, all of the gap grouting pipes are arranged in the gap between two adjacent steel caissons, and the lower part and the outer side of the capping beam are connected to the top end of the n-level steel caisson and the inner wall of the n-1-level steel caisson through pre-embedded steel bars, respectively;

[0014] a plurality of support brackets, the upper and lower ports of each n-level steel caisson segment of the n-level steel caisson are welded with a support bracket, respectively;

[0015] 4(n-1) counterforce steel bracket members, welded on the top inner wall of the lowermost segment of the n-1-level steel caisson, the top inner wall of the n-1-level steel caisson is uniformly ringed with four counterforce steel bracket members, and each counterforce steel bracket member comprises three counterforce steel brackets;

[0016] 4(n-1) double-stage hydraulic jacks, the bottom of each counterforce steel bracket member on the top inner wall of the n-1-level steel caisson is vertically installed with a double-stage hydraulic jack, and the top end of the installed double-stage hydraulic jack abuts against the support bracket of the top end of the n-level steel caisson.

[0017] Optionally, in the steel caisson vertical continuous pressing linkage device, the double-stage hydraulic jack comprises a primary piston rod, a secondary piston rod, a ball head seat, and a cylinder barrel, one end of the secondary piston rod is connected to the ball head seat, the other end of the secondary piston rod is sleeved in the primary piston rod, and the end of the primary piston rod away from the secondary piston rod is sleeved in the cylinder barrel.

[0018] Optionally, in the steel caisson vertical continuous pressing linkage device, the diameter of the cylinder barrel is 360 mm, the diameter of the primary piston rod is 270 mm, the diameter of the secondary piston rod is 170 mm, and the maximum extension range of the double-stage hydraulic jack is 3500 mm-4000 mm.

[0019] Optionally, in the steel caisson vertical continuous pressing linkage device, the support bracket comprises a steel plate body and an end head pad plate arranged at the end of the steel plate body.

[0020] Optionally, in the steel caisson vertical continuous pressing linkage device, the thickness of the steel plate body is 20 mm, the chamfer slope is controlled to be less than or equal to 1:6, and the thickness of the end head pad plate is 20 mm.

[0021] Optionally, in the steel caisson vertical continuous pressing linkage device, each gap grouting pipe is a φ48 patterned steel pipe, and the grouting hole spacing formed on the gap grouting pipe is less than or equal to 600 mm.

[0022] Optionally, in the steel caisson vertical continuous pressing relay device, the width of the capping beam is 500 mm, and the height is 600 mm.

[0023] Optionally, in the steel caisson vertical continuous pressing relay device, the number of the embedded steel member panels is 8, which are uniformly distributed along the inner ring of the counterweight ring beam, and the number of the connecting steel plates is 24.

[0024] The application also provides a construction method of the steel caisson vertical continuous pressing relay device, which comprises the following steps:

[0025] S1, lowering and locking of the first-stage steel caisson: based on the counterweight ring beam, all first-stage steel caisson segments are sequentially assembled and lowered by using a traditional pressing method, and after the first-stage steel caisson formed by splicing is lowered to a predetermined position, the first-stage steel caisson is locked on the counterweight ring beam;

[0026] S2, first-stage steel caisson excavation construction: while reserving a safe soil plug height, soil excavation in the first-stage steel caisson is performed;

[0027] S3, installation of reaction steel bracket components: four reaction steel bracket components are uniformly welded on the inner wall of the top end of the n-1 stage steel caisson in the ring direction; wherein n=H / h, n is the number of stages of the steel caisson, h is the single pressing depth, and the value range is 14-16 m; H is the total height of the steel caisson sinking, and n is an integer greater than or equal to 2;

[0028] S4, installation of double-stage hydraulic jacks: a double-stage hydraulic jack is vertically installed below the bottom end head pad plate of each reaction steel bracket component;

[0029] S5, lowering of the n-stage steel caisson: all n-stage steel caisson segments are sequentially assembled and lowered by using a traditional pressing method at a distance from the inner wall of the n-1 stage steel caisson, and the support bracket at the top end of the n-stage steel caisson abuts against the top end of the double-stage hydraulic jack;

[0030] S6, pushing and pressing of the double-stage hydraulic jack: the double-stage hydraulic jack is controlled to push and press, so that the n-stage steel caisson is pressed and sunk into place;

[0031] S7, gap grouting: grouting is performed in the gap between the n-1 stage steel caisson and the n-stage steel caisson;

[0032] S8, capping beam construction: a capping beam is formed at the top end of the n-stage steel caisson, and the lower part and the outer side of the capping beam are connected to the top end of the n-stage steel caisson and the inner wall of the n-1 stage steel caisson through embedded steel bars, respectively.

[0033] S9, excavating the nth steel caisson: after the concrete strength of the capping beam reaches 75%, excavate the earth inside the nth steel caisson;

[0034] S10, cyclically execute S3-S9 until the relay sinking of all levels of steel caissons is completed.

[0035] Optionally, in the construction method of the steel caisson vertical continuous pressing relay device, in S6, the working parameters of the double-stage hydraulic jack are as follows:

[0036] The pushing and pressing rate of the double-stage hydraulic jack is less than or equal to 5 cm / min, and the pushing pressure is controlled to be stepped up and extended according to 25%, 50%, 75%, and 100%.

[0037] In the steel caisson vertical continuous pressing relay device and the construction method thereof provided by the present application, the steel caisson vertical continuous pressing relay device has the following beneficial effects:

[0038] 1) According to the total height of the steel caisson sinking, the steel caisson is continuously pressed in relay in 2 levels or more levels (combined with requirements) in the vertical direction, so as to realize a 2-layer or multi-layer well wall structure in the plane position, enhance the bearing capacity of the well wall, effectively avoid local instability and buckling conditions, and ensure the structural stress safety of the large-depth vertical continuous pressing relay steel caisson.

[0039] 2) Each level of the steel caisson is divided into multiple segments for relay pressing, and the depth of each segment is reduced, so that the required reaction force of each segment is reduced.

[0040] 3) The depth-diameter ratio of each level of the stepped pressing is reduced compared with the depth-diameter ratio of the one-time pressing, and the stability and safety of the well wall under the action of the concentrated load of the pressing are also greatly enhanced. BRIEF DESCRIPTION OF DRAWINGS

[0041] The above and other objects, features and advantages of the present application will become more apparent from the following detailed description of exemplary embodiments of the present application taken in conjunction with the accompanying drawings, in which like reference characters refer to the like parts throughout the different views of the drawings.

[0042] Figure 1 is a construction section view of a steel caisson vertical continuous pressing relay device in an embodiment of the present application;

[0043] Figure 2 is a construction plan view of a steel caisson vertical continuous pressing relay device in an embodiment of the present application;

[0044] Figure 3 is a structure schematic view of a double-stage hydraulic jack in an embodiment of the present application;

[0045] Figure 4is a cross-sectional view of a steel caisson gap sealing member in an embodiment of the present application;

[0046] Figure 5 is a plan view of a steel caisson gap sealing member in an embodiment of the present application;

[0047] Figure 6 is a cross-sectional view after S4 is performed in an embodiment of the present application;

[0048] Figure 7 is a cross-sectional view after the second stage steel caisson is lowered and installed;

[0049] Figure 8 is a cross-sectional view of a second stage steel caisson being vertically and continuously pushed down and pressed in;

[0050] Figure 9 is a flow chart of a construction method of a steel caisson vertically and continuously pressed in.

[0051] In the drawings:

[0052] 1 - first stage steel caisson; 2 - second stage steel caisson; 3 - counterweight locking member; 31 - counterweight ring beam; 32 - pre-buried steel embedded panel; 33 - connecting steel plate; 4 - steel caisson gap sealing member; 41 - gap grouting pipe; 42 - capping beam; 5 - support bracket; 6 - reaction force steel bracket member; 7 - two-stage hydraulic jack; 71 - first stage piston rod; 72 - second stage piston rod; 73 - ball head seat; 74 - oil cylinder barrel. DETAILED DESCRIPTION

[0053] The present application is further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of the present application will become apparent from the following description and claims. It should be noted that the drawings are in extremely simplified form and are not drawn to precise scale, and are merely intended to facilitate the understanding of the embodiments of the present application.

[0054] The present application is further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of the present application will become apparent from the following description and claims. It should be noted that the drawings are in extremely simplified form and are not drawn to precise scale, and are merely intended to facilitate the understanding of the embodiments of the present application.

[0055] In the description of the invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the invention.

[0056] In addition, the terms "first", "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the invention, the meaning of "multiple" is two or more, unless otherwise specifically limited.

[0057] In the invention, unless otherwise specifically defined and limited, the terms "mounting", "connection", "connection", "fixing" and the like should be broadly understood, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the invention can be understood according to the specific circumstances.

[0058] Please refer to Figures 1 to 5 , the steel caisson vertical continuous pressing relay device comprises: a first stage steel caisson 1, an n-stage steel caisson, a counterweight locking member 3, n-1 steel caisson gap sealing members 4, a plurality of support corbels 5, 4(n-1) counterforce steel corbel members 6 and 4(n-1) double-stage hydraulic jacks 7, the first stage steel caisson 1 comprises a plurality of first stage steel caisson segments (such as Figure 1 , N1, N2, …, Ni), all the first stage steel caisson segments are vertically assembled to form the first stage steel caisson 1; the n-stage steel caisson is arranged inside the n-1-stage steel caisson, and the n-stage steel caisson comprises a plurality of n-stage steel caisson segments (such as Figure 1In the embodiment, W1, W2, …, Wi, all the n-level steel caisson segments are vertically spliced to form the n-level steel caisson; wherein, the diameter of the n-1-level steel caisson is 200m-300m larger than that of the n-level steel caisson; n=H / h, n is the number of the steel caisson and the number of the steel caisson, h is the single pressing depth, the value range is 14-16m; H is the total sinking height of the steel caisson, n is an integer greater than or equal to 2; the counterweight locking member 3 comprises a counterweight ring beam 31, a plurality of embedded steel buried panels 32 arranged in the counterweight ring beam 31, and a plurality of connecting steel plates 33, the counterweight ring beam 31 is arranged outside the first-level steel caisson 1, one end of every three connecting steel plates 33 is vertically fixed on the adjacent embedded steel buried panel 32, and the other end is vertically fixed on the wall of the first-level steel caisson 1; the n-1 steel caisson gap sealing member 4 comprises a plurality of gap grouting pipes 41 and a top sealing beam 42, all the gap grouting pipes 41 are arranged in the gap between the adjacent two-level steel caissons, and the lower part and the outer side of the top sealing beam 42 are connected with the top end of the n-level steel caisson and the inner wall of the n-1-level steel caisson respectively through embedded steel bars (an effective sealing system is formed between the gap channels to prevent seepage of the gap water); the plurality of support brackets 5, the upper port and the lower port of each n-level steel caisson segment of the n-level steel caisson are respectively welded with a support bracket 5; the 4(n-1) counterforce steel bracket members 6 are welded on the inner wall of the top end of the lowermost segment of the n-1-level steel caisson, and the inner wall of the top end of the n-1-level steel caisson is uniformly ringed with four counterforce steel bracket members 6; the bottom of each counterforce steel bracket member 6 on the inner wall of the top end of the n-1-level steel caisson is vertically installed with a double-stage hydraulic jack 7, and the top end of the installed double-stage hydraulic jack 7 is abutted with the support bracket 5 of the top end of the n-level steel caisson.

[0059] According to the total sinking height of the steel caisson, the steel caisson is vertically divided into two or more levels (combined with the demand) and continuously pressed in, so as to realize the two or more layer well wall structures in the plane position, enhance the bearing capacity of the well wall, effectively avoid the local instability and buckling condition, and ensure the structural stress safety of the large-depth vertical continuous pressing force steel caisson.

[0060] As shown in Figure 2 In the embodiment, the number of the embedded steel buried panels 32 is 8, which is uniformly distributed along the inner ring of the counterweight ring beam 31, and the number of the connecting steel plates 33 is 24, that is, every three connecting steel plates 33 form a group to establish the connection between the first-level steel caisson 1 and the counterweight ring beam 31.

[0061] As shown in Figure 3As shown, the double-stage hydraulic jack 7 comprises a first-stage piston rod 71, a second-stage piston rod 72, a ball head seat 73, and an oil cylinder barrel 74, one end of the second-stage piston rod 72 is connected with the ball head seat 73, the other end of the second-stage piston rod 72 is sleeved in the first-stage piston rod 71, and the end of the first-stage piston rod 71 away from the second-stage piston rod 72 is sleeved in the oil cylinder barrel 74. Wherein, the diameter of the oil cylinder barrel 74 is 360mm, the diameter of the first-stage piston rod 71 is 270mm, the diameter of the second-stage piston rod 72 is 170mm, and the maximum jacking range of the double-stage hydraulic jack 7 is 3500mm-4000mm.

[0062] Further, the support bracket 5 comprises a steel plate body and an end head pad plate arranged at the end of the steel plate body. In the embodiment, the thickness of the steel plate body is 20mm, the chamfer slope is controlled to be less than or equal to 1:6, and the thickness of the end head pad plate is 0mm.

[0063] In the embodiment, each gap grouting pipe 41 is preferably a φ48 patterned steel pipe, and a grouting hole is arranged on the gap grouting pipe 41 at an interval of less than or equal to 600mm; the width of the capping beam 42 is 500mm, and the height is 600mm.

[0064] The vertical continuous pressing relay device of the steel caisson provides a counterforce for the pressing of the next-stage steel caisson by the frictional force of the steel caisson that has been lowered and the lowered front-stage steel caisson, so that the longitudinal depth of the steel caisson can be continuously developed, and the pressing depth of the relay can be easily realized as 40m. The problems of insufficient counterforce for the pressing of the steel caisson and instability of the shaft wall under large load are solved, and the pressing depth of the steel caisson and the safety of the project are ensured.

[0065] Correspondingly, the embodiment also provides a construction method of the vertical continuous pressing relay device of the steel caisson. In the embodiment, the structure and the construction process of the vertical continuous pressing relay device of the steel caisson are displayed by taking n=2 as an example. The vertical continuous pressing relay device of the steel caisson comprises a first-stage steel caisson and a second-stage steel caisson, the second-stage steel caisson is arranged in the first-stage steel caisson, and a counterforce bracket component is arranged on the inner wall of the top end of the first-stage steel caisson. The process of n>2 can be analogized.

[0066] The construction method of the vertical continuous pressing relay device of the steel caisson will be described in detail below. Figures 1 to 9 The construction method of the vertical continuous pressing relay device of the steel caisson will be described in detail below.

[0067] Firstly, step S1, the first stage steel caisson 1 is lowered and locked: based on the counterweight ring beam 31, all the first stage steel caisson segments are sequentially assembled and lowered by using the traditional pressing method, and after the first stage steel caisson 1 formed by splicing is lowered to the predetermined position, the first stage steel caisson 1 is locked on the counterweight ring beam 31; mainly through the connection steel plates 33, every three connection steel plates 33 form a group, and the plane is divided into 8 equal parts at 360°, one end is vertically welded on the adjacent pre-buried steel embedded panel 32, and the other end is vertically welded on the wall of the first stage steel caisson 1.

[0068] Then, step S2, the first stage steel caisson 1 is excavated and constructed: while reserving the safety soil plug height, the earthwork excavation in the first stage steel caisson 1 is carried out; here, the soil plug height is generally controlled to be 5-6 m.

[0069] Then, step S3, the reaction force steel corbel component 6 is installed: four reaction force steel corbel components 6 are evenly welded on the inner wall of the top end of the n-1 stage steel caisson in the circumferential direction; wherein, n=H / h, H is the total height of the steel caisson sinking, n is the stage number of the steel caisson, n is an integer greater than or equal to 2; h is the single pressing depth, the value range is 14-16 m, that is, the sinking depth of each stage of the steel caisson is controlled to be about 14-16 m; the selection of the numerical value is mainly combined with the experience data of the steel caisson pressing, and when the single pressing depth is 14-16 m, the pressing force is generally not greater than 250 t, which is not large and easy to control. The reaction force steel corbel component 6 includes three reaction force steel corbel plates, each reaction force steel corbel plate is 20 mm thick, the chamfer slope is controlled to be not greater than 1:6, the bottom is provided with an end pad (about 20 mm thick), the plane is divided into 4 equal parts at 360°, and each reaction force steel corbel component 6 is welded on the inner side wall of the n-1 stage steel caisson, the effective weld height is not less than 10 mm, and the control distance is about 4-6 m from the top of the soil plug reserved for the n-1 stage steel caisson earth excavation.

[0070] Next, please refer to Figure 6 and Figure 7 , step S4, the double-stage hydraulic jack 7 is installed: a double-stage hydraulic jack 7 is vertically installed below the bottom end pad of each reaction force steel corbel component 6, and the installation process ensures that the double-stage hydraulic jack 7 is in a vertical state, and the vertical control is not greater than 1 / 300.

[0071] Next, please refer to Figure 7 , step S5, the n stage steel caisson is lowered: the n stage steel caisson segments are sequentially assembled and lowered by using the traditional pressing method, the top end of the n stage steel caisson is abutted with the top end of the double-stage hydraulic jack 7, and the n stage steel caisson is divided into multiple segments for relay pressing, the stage relay pressing, the pressing depth of each segment is reduced, and the reaction force required for each segment pressing is reduced.

[0072] Specifically, after the large-stroke two-stage hydraulic jack 7 is installed, the n-th stage steel caisson is lowered, and the diameter of the n-th stage steel caisson is controlled to be 200-300 mm smaller than that of the (n-1)-th stage steel caisson, so as to provide a space for hoisting and lowering operation. The depth-diameter ratio of each stage is reduced compared with the depth-diameter ratio of one-time lowering, and the stability and safety of the well wall are greatly enhanced under the action of concentrated load of lowering.

[0073] After the n-th stage steel caisson is lowered and positioned, support brackets 5 are welded at the positions corresponding to the jacking positions of the two-stage hydraulic jack 7 at the upper and lower ports of the segment. The support bracket 5 is made of steel plate with a thickness of about 20 mm, and the chamfer slope is controlled to be not greater than 1:6. An end pad (with a thickness of about 20 mm) is arranged at the end. The support bracket 5 bears the downward reaction force of the jacking of the large-stroke two-stage hydraulic jack 7 of the upper stage, and also reduces the stress concentration at the force point of the secondary inner segment steel caisson.

[0074] Next, referring to Figure 8 , step S6 is performed, and the two-stage hydraulic jack 7 is jacked and lowered: the two-stage hydraulic jack 7 is controlled to be jacked and lowered, so that the n-th stage steel caisson is pressed and sunk into position; wherein the jacking and lowering speed of the two-stage hydraulic jack 7 is less than or equal to 5 cm / min, the jacking pressure is controlled to be stepped up and extended by 25%, 50%, 75%, and 100%, and the pressure difference of each two-stage hydraulic jack 7 is not greater than 5 tons, so as to ensure the stable and vertical lowering of the corresponding steel caisson segment.

[0075] Next, referring to Figure 4 and Figure 5 , step S7 is performed, and the gap is grouted: the gap between the (n-1)-th stage steel caisson and the n-th stage steel caisson is grouted.

[0076] Specifically, before the n-th stage steel caisson is pressed and sunk into position and excavated, the gap between the n-th stage steel caisson and the (n-1)-th stage steel caisson is grouted and waterproofed. The grouting pipe is φ48×3 patterned steel pipe, the grouting depth is ≥6 m, the grouting hole spacing is not greater than 600 mm, and the slurry is uniformly distributed along the ring. The main raw material of the slurry is P.O42.5 grade cement, the water-cement ratio is 0.55-0.65, the grouting pressure is controlled to be 2-3 MPa, and the injection speed is controlled to be 32-47 L / min. When the pressure is too high, the speed should be low, and when the pressure is too low, the speed should be high.

[0077] Next, referring to Figure 4 and Figure 5 , step S8 is performed, and the top beam 42 is constructed: the top beam 42 is poured at the top end of the n-th stage steel caisson, and the lower part and the outer side of the top beam 42 are connected to the top end of the n-th stage steel caisson and the inner wall of the (n-1)-th stage steel caisson through pre-embedded steel bars, respectively.

[0078] Specifically, the C35 top sealing beam 42 (the top sealing beam 42 is about 500 mm wide and about 600 mm high) is cast at the top end of the nth stage steel caisson, and the lower part and the outer side of the top sealing beam 42 are connected to the inner and outer steel caissons through embedded steel bars. In combination with gap grouting, an effective sealing system of the gap channel between the two is formed, preventing seepage of the gap water, and the circular ring support stiffness of the top sealing beam 42 is also conducive to the circumferential support of the well wall and the deformation control.

[0079] Then, step S9 is performed, and the nth stage steel caisson is excavated and constructed: after the concrete strength of the top sealing beam 42 reaches 75%, the earthwork excavation in the nth stage steel caisson is performed.

[0080] Then, step S10 is performed, and steps S3-S9 are repeatedly performed until the relay sinking of all stages of steel caissons is completed.

[0081] It should be noted that, for the foregoing method embodiments, in order to simply describe, they are all expressed as a series of action combinations, but those skilled in the art should know that the present application is not limited by the action sequence described, because according to the present application, certain steps can be performed in other sequences or simultaneously. Secondly, those skilled in the art should know that the embodiments described in the specification all belong to preferred embodiments, and the actions and modules involved are not necessarily required by the present application.

[0082] In the above embodiments, the description of each embodiment is focused on, and the parts not described in detail in a certain embodiment can be referred to the related description of other embodiments.

[0083] The present application has the following advantages:

[0084] 1) According to the total height of the steel caisson sinking, the steel caisson is divided into 2 stages or more stages (combined with the requirements) and is continuously pressed in, so as to realize the 2-layer or multi-layer well wall structure in the plane position, enhance the bearing capacity of the well wall, effectively avoid the local instability and buckling condition, and ensure the structural stress safety of the large-depth vertical continuous pressure relay steel caisson.

[0085] 2) Each stage of the steel caisson is divided into multiple segments for relay sinking, the sinking depth of each segment is reduced, and the required reaction force of each segment is reduced.

[0086] 3) The depth-diameter ratio of each stage of the grading is reduced compared with the depth-diameter ratio of one-time sinking, and the stability and safety of the well wall under the action of the concentrated load of sinking are also greatly enhanced.

[0087] The above description is only a description of the preferred embodiments of the present application, and does not limit the scope of the present application in any way, and any modification or modification of the present application by those skilled in the art according to the above disclosure is within the protection scope of the claims.

Claims

1. A steel caisson vertical continuous pressing relay device, characterized by, The utility model relates to a steel sinking well structure, including: A first-stage steel sinking well comprises a plurality of first-stage steel sinking well segments, all of which are vertically assembled to form the first-stage steel sinking well; An nth-stage steel sinking well is arranged inside an (n-1)th-stage steel sinking well, and the nth-stage steel sinking well comprises a plurality of nth-stage steel sinking well segments, all of which are vertically assembled to form the nth-stage steel sinking well; wherein the diameter of the (n-1)th-stage steel sinking well is larger than that of the nth-stage steel sinking well; n = H / h, n is the number of stages and the number of steel sinking wells, h is the single-time pressing depth, and the value range is 14-16 m; H is the total height of the steel sinking well, and n is an integer greater than or equal to 2; A counterweight locking member comprises a counterweight ring beam, a plurality of embedded steel embedded part panels arranged inside the counterweight ring beam, and a plurality of connecting steel plates, the counterweight ring beam is arranged outside the first-stage steel sinking well, one end of every three connecting steel plates is fixed vertically on the adjacent embedded steel embedded part panel, and the other end is fixed vertically on the well wall of the first-stage steel sinking well; n-1 steel sinking well gap sealing members comprise a plurality of gap grouting pipes and a capping beam, all of the gap grouting pipes are arranged in the gap between two adjacent stages of steel sinking wells, and the lower part and the outer side of the capping beam are connected to the top end of the nth-stage steel sinking well and the inner wall of the (n-1)th-stage steel sinking well through embedded steel bars respectively; A plurality of support corbels are welded to the upper end and the lower end of each nth-stage steel sinking well segment of the nth-stage steel sinking well; 4(n-1) counterforce steel corbel members are welded to the inner wall of the top end of the (n-1)th-stage steel sinking well, the inner wall of the top end of the (n-1)th-stage steel sinking well is uniformly provided with four counterforce steel corbel members, and each counterforce steel corbel member comprises three counterforce steel corbels; 4(n-1) double-stage hydraulic jacks are vertically installed at the bottom of each counterforce steel corbel member on the inner wall of the top end of the (n-1)th-stage steel sinking well, and the top end of the installed double-stage hydraulic jack abuts against the support corbel of the top end of the nth-stage steel sinking well.

2. The steel caisson vertical continuous pressing relay device according to claim 1, wherein The double-stage hydraulic jack comprises a primary piston rod, a secondary piston rod, a ball head seat and an oil cylinder barrel, one end of the secondary piston rod is connected to the ball head seat, the other end of the secondary piston rod is sleeved in the primary piston rod, and one end of the primary piston rod away from the secondary piston rod is sleeved in the oil cylinder barrel.

3. The steel caisson vertical continuous pressing relay device according to claim 2, wherein The diameter of the oil cylinder barrel is 360 mm, the diameter of the primary piston rod is 270 mm, the diameter of the secondary piston rod is 170 mm, and the maximum jacking amount of the double-stage hydraulic jack ranges from 3500 mm to 4000 mm.

4. The steel caisson vertical continuous pressing relay device according to claim 1, wherein The support corbel comprises a steel plate body and an end head pad plate arranged at the end of the steel plate body.

5. The steel caisson vertical continuous pressing relay device according to claim 4, wherein The thickness of the steel plate body is 20 mm, the chamfer slope is controlled to be less than or equal to 1:6, and the thickness of the end head pad plate is 20 mm.

6. The steel caisson vertical continuous pressing relay device according to any one of claims 1 to 5, characterized by Each gap grouting pipe is a φ48 patterned steel pipe, and the grouting holes arranged thereon are spaced apart by a distance of less than or equal to 600 mm.

7. The steel caisson vertical continuous pressing relay device according to any one of claims 1 to 5, characterized by The width of the capping beam is 500 mm, and the height is 600 mm.

8. The steel caisson vertical continuous pressing relay device according to any one of claims 1 to 5, wherein The number of the embedded steel embedded part panels is 8, which are evenly distributed along the inner ring of the counterweight ring beam, and the number of the connecting steel plates is 24.

9. A method of construction of a steel caisson vertical continuous pressing into a relay device according to any one of claims 1 to 8, characterized in that, The method comprises the following steps: S1, lowering and locking of the first-stage steel caisson: based on the counterweight ring beam, all first-stage steel caisson segments are sequentially and sectionally assembled and lowered by using the traditional pressing-in method, and after the first-stage steel caisson formed by splicing is lowered to the predetermined position, the first-stage steel caisson is locked on the counterweight ring beam; S2, first-stage steel caisson excavation construction: while reserving the safety soil plug height, the soil excavation in the first-stage steel caisson is performed; S3, installation of reaction steel corbel components: four reaction steel corbel components are evenly welded on the inner wall of the top end of the n-1 stage steel caisson in the ring direction; wherein n=H / h, n is the number of stages of the steel caisson, h is the single-time pressing depth, and the value range is 14-16 m; H is the total height of the steel caisson sinking, and n is an integer greater than or equal to 2; S4, installation of double-stage hydraulic jacks: a double-stage hydraulic jack is vertically installed under the bottom end head pad plate of each reaction steel corbel component; S5, lowering of the n-stage steel caisson: at a distance from the inner wall of the n-1 stage steel caisson, all n-stage steel caisson segments are sequentially and sectionally assembled and lowered by using the traditional pressing-in method, and the support corbel at the top end of the n-stage steel caisson abuts against the top end of the double-stage hydraulic jack; S6, pushing and pressing of the double-stage hydraulic jack: the double-stage hydraulic jack is controlled to push and press, so that the n-stage steel caisson is pressed and sunk into place; S7, gap grouting: grouting is performed in the gap between the n-1 stage steel caisson and the n-stage steel caisson; S8, construction of the capping beam: the capping beam is formed by pouring at the top end of the n-stage steel caisson, and the lower part and the outer side of the capping beam are connected to the top end of the n-stage steel caisson and the inner wall of the n-1 stage steel caisson through embedded steel bars, respectively; S9, n-stage steel caisson excavation construction: after the concrete strength of the capping beam reaches 75%, the soil excavation in the n-stage steel caisson is performed; S10, cyclic execution of S3-S9, until the relay sinking of all stages of steel caissons is completed.

10. The construction method of a steel caisson vertical continuous pressing into a relay device according to claim 9, characterized in that, In S6, the working parameters of the double-stage hydraulic jack are as follows: The pushing and pressing rate of the double-stage hydraulic jack is less than or equal to 5 cm / min, and the pushing pressure is controlled to be graded and pressed and extended according to 25%, 50%, 75% and 100%.

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