A construction method of a foundation pit continuous wall

Abstract

The application discloses a construction method of a foundation pit continuous wall and relates to the technical field of deep foundation pit support in building engineering. A starting well and a receiving well are arranged at four corners of a predicted foundation pit respectively, a continuous wall prefabricated block is hoisted in sections in the starting well, a plurality of continuous wall prefabricated blocks are formed into a continuous wall prefabricated block through temporary fixing measures, after the excavation of a section of a groove section is completed, a continuous wall prefabricated block is immediately pushed through a pushing system, the installation and pushing of the continuous wall prefabricated block are repeated until the first continuous wall prefabricated block is pushed to the receiving well, then the pushing direction of the pushing device is reversed, the pushing construction of the continuous wall between the starting well and another receiving well is continuously performed, after the pushing construction of the continuous wall between all the starting wells and the receiving wells is completed, end treatment of adjacent continuous walls in the wells is performed. Compared with the prior art, the construction method of the foundation pit continuous wall can reduce the construction difficulty of the continuous wall and save the construction period.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of deep foundation pit support, and particularly relates to a construction method of a foundation pit diaphragm wall. BACKGROUND

[0002] The underground diaphragm wall is the most powerful and effective large foundation pit support form in the current foundation pit engineering. By means of various trenching machines and the wall protection of mud, a narrow and deep trench is dug underground, and appropriate materials are poured in the trench to form a continuous underground wall body with the functions of seepage prevention, waterproof, soil retaining and load bearing. The construction has small vibration, large wall rigidity, good integrity and fast construction speed, and can save earthwork, and can be used for constructing deep foundation pit support in dense building groups and for reverse construction method construction, and can be used in various geological conditions, including sandy soil layer and sand and gravel layer with a particle size of less than 50 mm. It is suitable for constructing the basement of a building, underground shopping mall, parking lot, underground oil depot, retaining wall, deep foundation of high-rise building, reverse construction method enclosure structure, deep pool and pit of industrial building, and vertical shaft. At present, the construction of the underground diaphragm wall mainly adopts the cast-in-place concrete construction technology, but there are the following problems: 1. In some special geological conditions (such as very soft silt soil, deep sand layer and alluvial layer containing boulders), the construction difficulty is very large; 2. The process of the underground diaphragm wall is invisible, the joint position processing of adjacent concrete sections is difficult, and the problems of misalignment of adjacent wall sections and water leakage are prone to occur; 3. The quality of the wall surface of the cast-in-place structure is poor, and the phenomenon of exposed steel bars often occurs; and 4. In urban construction, the treatment of waste mud slurry is relatively troublesome. SUMMARY

[0003] The present application aims to at least solve one of the above technical problems in the prior art to some extent. To this end, the present application provides a construction method of a foundation pit diaphragm wall, which reduces the construction difficulty of the diaphragm wall, saves the construction period, and further solves the problems of misalignment of adjacent diaphragm wall sections and water leakage.

[0004] The construction method of the foundation pit diaphragm wall according to the present application embodiment comprises the following steps:

[0005] S1, two starting wells and two receiving wells are arranged, the connecting lines of the two starting wells and the two receiving wells form a rectangle, and the two starting wells are arranged diagonally in the rectangle;

[0006] S2, two rows of guide walls are constructed between the starting wells and the receiving wells;

[0007] S3, a jacking system is arranged in the starting well, and production and manufacturing of continuous wall prefabricated blocks are performed;

[0008] S4, the continuous wall prefabricated block is assembled into a continuous wall prefabricated block, and the continuous wall construction between the starting well and one of the receiving wells is performed; during the construction, a slot section is excavated between the two rows of guide walls, and the continuous wall prefabricated block is pushed through the pushing system until the first continuous wall prefabricated block enters the receiving well;

[0009] S5, the orientation of the pushing system is turned, and the continuous wall construction between the starting well and another receiving well is performed; during the construction, a slot section is excavated between the two rows of guide walls, and the continuous wall prefabricated block is pushed through the pushing system until the first continuous wall prefabricated block enters the receiving well;

[0010] S6, when the continuous wall between the starting well and the receiving well is pushed into place, the end cast-in-place section construction of the two adjacent rows of continuous walls is performed;

[0011] S7, the pushing device in the starting well is removed, and the starting well and the receiving well are backfilled.

[0012] According to the construction method of the foundation pit continuous wall, in the step S4 or the step S5, the two starting wells respectively face different receiving wells for synchronous construction of the continuous wall.

[0013] According to the construction method of the foundation pit continuous wall, when the continuous wall construction is performed, after the assembly of the first continuous wall prefabricated block is completed, the first continuous wall prefabricated block is lowered into the starting well, the advancing end of the first continuous wall prefabricated block is provided with a pushing head, after the excavation of the first slot section is completed, the first continuous wall prefabricated block is pushed into the first slot section through the pushing system, and after each slot section is excavated, a continuous wall prefabricated block is added to the starting well, and the continuous wall is formed by the connection of the continuous wall prefabricated blocks.

[0014] According to the construction method of the foundation pit continuous wall, when the first continuous wall prefabricated block approaches the receiving well, a first slot hole is formed in the well wall of the receiving well by using a water drill or a rope saw, the first slot hole is provided with a steel structure door sleeve for receiving the first continuous wall prefabricated block, and a high-pressure rotary jet pile is constructed outside the outlet of the first slot hole.

[0015] According to the construction method of the foundation pit continuous wall, in the step S3, after the pushing system is installed, a second slot hole is formed in the well wall of the starting well by using a water drill or a rope saw, the steel structure door sleeve is installed around the second slot hole, and a high-pressure rotary jet pile is constructed at the inlet of the second slot hole.

[0016] According to the construction method of the foundation pit continuous wall, after the continuous wall between the starting well and the receiving well is pushed into position, grouting treatment is performed between the steel structure door pocket and the continuous wall.

[0017] According to the construction method of the foundation pit continuous wall, the pushing system comprises a three-dimensional pushing assembly, a sliding rail assembly and a controller for controlling the three-dimensional pushing assembly, the controller is arranged outside the starting well, a back wall for mounting the three-dimensional pushing assembly is arranged in the starting well, and the sliding rail assembly is arranged at the bottom of the starting well and is used for assisting sliding of the continuous wall prefabricated blocks.

[0018] According to the construction method of the foundation pit continuous wall, the sliding rail assembly comprises a groove sliding rail and a bottom plate, the bottom plate is made of reinforced concrete, the groove sliding rail is U-shaped and is fixed to the bottom plate, and steel balls are arranged in the groove sliding rail.

[0019] According to the construction method of the foundation pit continuous wall, the side surface of the continuous wall prefabricated block is provided with a connecting groove for butt joint, two adjacent continuous wall prefabricated blocks are butt jointed by an arc-shaped bolt, the arc-shaped bolt passes through the connecting groove, and grouting holes and round holes are arranged between two ends of the continuous wall prefabricated block.

[0020] According to the construction method of the foundation pit continuous wall, the guide wall is further provided with a guide device, the guide device comprises a portal frame arranged between two rows of guide walls and a sliding member for assisting sliding movement of the portal frame, and the portal frame is provided with a limiting piece at a position aligned with the groove section.

[0021] Based on the above technical scheme, the embodiment of the present application has at least the following beneficial effects: in the above technical scheme, the originating well and the receiving well are respectively arranged at the four corners of the predicted foundation pit, the continuous wall prefabricated block is hoisted in sections in the originating well, the multiple continuous wall prefabricated blocks are formed into a continuous wall prefabricated block through temporary fixing measures, after the excavation of a section of the slot is completed, a continuous wall prefabricated block is immediately pushed by the jacking system, the installation and pushing of the continuous wall prefabricated block are repeated until the first continuous wall prefabricated block is pushed to the receiving well, then the pushing direction of the jacking device is reversed, and the pushing construction of the continuous wall between the originating well and another receiving well is continued, after the jacking construction of the continuous wall between all the originating wells and receiving wells is completed, the end treatment of the adjacent continuous wall in the well is performed. Compared with the prior art, the construction method of the present application can be used in some special geological conditions (such as very soft silt soil, deep sand layer, and alluvial layer containing boulders), and the construction is simple. The continuous wall prefabricated block is prefabricated outside the field first, assembled into a continuous wall prefabricated block on site, pushed into place by the jacking system, and finally formed into a closed underground continuous wall structure by pouring reinforced concrete at the end. Compared with the original cast-in-place construction, the quality is more controllable and more secure, the whole process is dry construction, the waterproofing and connection treatment between the segments of the underground continuous wall are more convenient, the quality and effect are more intuitive, the assembly type construction of the underground continuous wall is realized, the wall size and connection mode can be adjusted according to the geological conditions, the construction process is adjustable, and the cost is controllable. BRIEF DESCRIPTION OF DRAWINGS

[0022] The present application will be further described below in conjunction with the drawings and examples.

[0023] Figure 1 is a schematic diagram of the continuous wall construction between the originating well and the receiving well in the embodiment of the present application Figure One ;

[0024] Figure 2 is a schematic diagram of the continuous wall construction between the originating well and the receiving well in the embodiment of the present application Figure Two ;

[0025] Figure 3 is a schematic diagram of the continuous wall construction between the originating well and the receiving well in the embodiment of the present application Figure Three ;

[0026] Figure 4 is a schematic diagram of the continuous wall construction between the originating well and the receiving well in the embodiment of the present application Figure Four ;

[0027] Figure 5 is a schematic diagram of the connection between the originating well and the jacking device in the embodiment of the present application Figure One ;

[0028] Figure 6 is a schematic diagram of the connection between the originating well and the jacking device in the embodiment of the present applicationFigure Two ;

[0029] Figure 7 This is a schematic diagram of the slide rail assembly in an embodiment of the present invention;

[0030] Figure 8 This is a schematic diagram of the prefabricated block structure of the continuous wall in an embodiment of the present invention;

[0031] Figure 9 This is a schematic diagram of the structure of a precast continuous wall block in an embodiment of the present invention;

[0032] Figure 10 This is a schematic diagram of the guiding device in an embodiment of the present invention. Figure One ;

[0033] Figure 11 This is a schematic diagram of the guiding device in an embodiment of the present invention. Figure Two . Detailed Implementation

[0034] This section will describe in detail specific embodiments of the present invention. Preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the drawings is to supplement the textual description with graphics, so that people can intuitively and vividly understand each technical feature and overall technical solution of the present invention, but they should not be construed as limiting the scope of protection of the present invention.

[0035] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0036] In the description of this invention, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0037] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0038] Underground continuous wall is a kind of foundation engineering, which uses a kind of trenching machine on the ground, excavates a long and narrow deep trench along the axis of the deep excavation engineering under the condition of mud protection, after cleaning the trench, hoists the reinforcement cage in the trench, then pours the underwater concrete by the guide pipe method to build a unit trench section, and so on, to build a continuous reinforced concrete wall underground, as a water cutting, anti-seepage, load-bearing and water retaining structure. However, the existing underground continuous wall mainly adopts the forming method of cast-in-place concrete, which has the following disadvantages: 1. It is very difficult to construct under some special geological conditions (such as very soft silt soil, deep sand layer, and alluvial layer containing boulders); 2. The process of underground continuous wall is invisible, and it is difficult to handle the joint position of adjacent concrete sections, and the problems of misalignment of adjacent wall sections and water leakage are prone to occur; 3. The quality of the wall surface of the cast-in-place structure is poor, and the phenomenon of exposed reinforcement often occurs; 4. When constructing in the city, the treatment of waste mud slurry is more troublesome.

[0039] As shown in Figure 1 , the embodiment of the present application provides a new construction method of foundation continuous wall, which can carry out efficient and safe continuous wall construction. Specifically, the method comprises the following steps:

[0040] S1, two starting wells 110 and two receiving wells 120 are arranged, and the connecting lines of the two starting wells 110 and the two receiving wells 120 form a rectangle, and the two starting wells 110 are arranged diagonally in the rectangle;

[0041] S2, two rows of guide walls 130 are constructed between the starting well 110 and the receiving well 120;

[0042] S3, a jacking system is arranged in the starting well 110, and the production and manufacturing of the continuous wall prefabricated blocks 310 are carried out;

[0043] S4, as shown in Figure 2 , the continuous wall prefabricated blocks 310 are assembled into the continuous wall prefabricated block 300, and the construction of the continuous wall 500 between the starting well 110 and one receiving well 120 is carried out. During the construction, the trench section is excavated between the two rows of guide walls 130, and the continuous wall prefabricated block 300 is pushed forward by the jacking system until the first continuous wall prefabricated block 300 enters the receiving well 120;

[0044] S5, the orientation of the jacking system is turned, and the construction of the continuous wall 500 between the starting well 110 and the other receiving well 120 is carried out. During the construction, the trench section is excavated between the two rows of guide walls 130, and the continuous wall prefabricated block 300 is pushed forward by the jacking system until the first continuous wall prefabricated block 300 enters the receiving well 120;

[0045] S6, as shown in Figure 3 and Figure 4As shown, after the diaphragm wall 500 between the launching shaft 110 and the receiving shaft 120 is pushed into place, the end cast-in-place section 140 of the two adjacent rows of diaphragm walls 500 is constructed;

[0046] S7, remove the pushing device in the launching shaft 110, and backfill the soil in the launching shaft 110 and the receiving shaft 120.

[0047] Specifically, the launching shaft 110 is used for the installation, pushing and integrated construction of the diaphragm wall 500. The launching shaft 110 is a reinforced concrete structure, which is square in plan and has a depth determined according to the height of the diaphragm wall 500, and is constructed by the sinking well method or the top-down method. Angle braces are arranged at the four corners of the shaft. The sinking well method is used to construct the launching shaft 110, and the concrete is poured after the reinforcement is reserved. The top-down method is used to construct the launching shaft 110, and the construction is synchronized with the shaft wall. Two steel door frames 111 are arranged in the shaft, which are installed on the side of the pushing direction of the diaphragm wall precast block 300, and are used to assist the pushing of the diaphragm wall precast block 300 and prevent water and external silt from entering the launching shaft 110. Before the steel door frame 111 is installed, two rows of detachable steel pipe concrete counter braces are arranged, which are vertically and spacedly arranged and consistent with the plane position of the angle braces, and the steel pipe support points are beside the distribution beam and the steel door frame 111. A closed circle is arranged from the top of the steel door frame 111 to the top of the launching shaft, which does not affect the pushing construction of the diaphragm wall precast block 300.

[0048] The receiving shaft 120 is used for the receiving and integrated construction of the diaphragm wall precast block 300. The receiving shaft 120 is a reinforced concrete structure, which is square in plan and has a depth determined according to the height of the diaphragm wall precast block 300, and the top of the receiving shaft 120 is higher than the top of the diaphragm wall precast block 300. The receiving shaft 120 is constructed by the sinking well method or the top-down method. Angle braces and cross braces are arranged at a corner of the receiving shaft 120, which are vertically and spacedly arranged and are reinforced concrete structures. The sinking well method is used to construct the receiving shaft 120, and the concrete is poured after the reinforcement is reserved. The top-down method is used to construct the receiving shaft 120, and the construction is synchronized with the shaft wall. Two steel door frames 111 are arranged in the receiving shaft 120, which are installed on the side of the pushing direction of the diaphragm wall precast block 300, and are used to assist the receiving of the diaphragm wall precast block 300 and prevent water and external silt from entering the receiving shaft 120. One row of detachable steel pipe concrete counter braces is arranged in the receiving shaft 120, which are vertically and spacedly arranged and staggered with the plane position of the angle braces, and the steel pipe support points are beside the distribution beam and the door frame of the shaft wall.

[0049] The diaphragm wall precast block 310 is hoisted in the launching shaft 110 in sections. The diaphragm wall precast block 310 forms the diaphragm wall precast block 300 through temporary fixing measures. After each section is completed, a section is immediately pushed through the pushing system, and the installation and pushing of the diaphragm wall precast block 300 are repeated. It should be noted that two launching shafts 110 are respectively directed towards different receiving shafts 120 for the simultaneous construction of the diaphragm wall 500, which can speed up the construction progress of the diaphragm wall 500 and shorten the construction period, and also does not need to be static like the cast-in-place underground diaphragm wall and wait for the underground diaphragm wall to solidify.

[0050] In some embodiments, when the construction of the continuous wall is carried out, after the assembly of the first continuous wall prefabricated block 300 is completed, the first continuous wall prefabricated block 300 is lowered into the starting well 110, wherein the advancing end of the first continuous wall prefabricated block 300 is provided with a jacking head 230, after the excavation of the first slot section is completed, the first continuous wall prefabricated block 300 is jacked into the first slot section through the jacking system, and after each slot section is excavated, a new continuous wall prefabricated block 300 is added into the starting well 110, and a plurality of continuous wall prefabricated blocks 300 are spliced into the continuous wall 500 as shown in Figure 3 or Figure 4 .

[0051] The jacking head 230 is composed of thick steel plates, steel rib plates, angle steels and channel steels, the front end is semicircular, the outer surface is a thick steel plate, the height is consistent with the underground continuous wall, the bottom is sealed, the top is open, the top angle steel is connected and fixed with the guide system H-shaped steel through welding, the jacking head 230 is designed with a circular arc or a front narrow and rear wide structure, so as to avoid the accumulation of soil and sand in front of the jacking, reduce the resistance in front of the jacking of the continuous wall prefabricated block 300, protect the reserved steel bars of the first continuous wall prefabricated block 300, and ensure that the cast-in-situ construction of the end of the continuous wall 500 can be realized.

[0052] Further, when the first continuous wall prefabricated block 300 approaches the receiving well 120, a first slot hole is formed in the well wall of the receiving well 120 by using a water drill or a rope saw, the first slot hole is provided with a steel structure door pocket 111 for assisting the receiving of the first continuous wall prefabricated block 300, and a high-pressure rotary jet pile 112 is constructed outside the outlet of the first slot hole, the high-pressure rotary jet pile 112 can reinforce the ground and effectively guide the continuous wall prefabricated block 300 into the steel structure door pocket 111. It should be noted that after the jacking system is installed, a second slot hole is formed in the well wall of the starting well 110 by using a water drill or a rope saw, the periphery of the second slot hole is provided with a steel structure door pocket 111, and a high-pressure rotary jet pile 112 is constructed at the inlet of the second slot hole, the high-pressure rotary jet pile 112 can reinforce the ground and effectively guide the continuous wall prefabricated block 300 into the steel structure door pocket 111. The steel structure door pocket 111 is processed from steel plates and steel rib plates, and is mainly used when the continuous wall prefabricated block 300 is jacked out of the well and jacked into the well. The bottom is provided with a groove type steel ball sliding rail, and the periphery is provided with a rubber water stop curtain. The height of the steel structure door pocket 111 of the receiving well 120 is higher than that of the steel structure door pocket 111 of the starting well 110. The steel structure door pocket 111 is installed inside the starting well 110 or the receiving well 120, and serves as a passage for the continuous wall prefabricated block 300 to be jacked out of the well or jacked into the well. At the same time, the steel structure door pocket 111 can prevent the soil outside the well from entering the well, and protect the well wall after the opening from being damaged by collision.

[0053] In some embodiments, after the diaphragm wall 500 between the originating well 110 and the receiving well 120 is positioned, grouting is performed between the steel structure door pocket 111 and the diaphragm wall 500 to achieve complete connection between the diaphragm wall 500 and the steel structure door pocket 111, and to avoid the soil outside the well from entering the well, thereby preparing for subsequent construction.

[0054] In some other embodiments, as shown in Figure 5 and Figure 6 , the pushing system includes a three-dimensional pushing assembly 220, a sliding rail assembly 150, and a controller for controlling the three-dimensional pushing assembly 220, the controller is arranged outside the originating well 110, a back wall 210 for installing the three-dimensional pushing assembly 220 is arranged in the originating well 110, and the sliding rail assembly 150 is arranged at the bottom of the originating well 110 and is used to assist the sliding of the diaphragm wall precast block 300. Specifically, as shown in Figure 7 , the sliding rail assembly 150 includes a groove sliding rail 152 and a bottom plate 151, the bottom plate 151 is made of reinforced concrete, the groove sliding rail 152 is U-shaped and is fixed to the bottom plate 151, and steel balls 153 are laid in the groove sliding rail 152. The controller drives the three-dimensional pushing assembly 220 to generate a horizontal pushing force, so as to facilitate the pushing of the diaphragm wall precast block 300 in the originating well 110 into the slot, thereby solving the problem of the dynamic force of the assembled diaphragm wall precast block 300 entering the soil, and the arrangement of the sliding rail assembly 150 can reduce the resistance of the three-dimensional pushing assembly 220 pushing against the diaphragm wall precast block 300, thereby effectively improving the pushing efficiency.

[0055] As shown in Figure 8 and Figure 9As shown, the side of the continuous wall prefabricated block 310 is provided with a connecting groove 314 for butt joint, two adjacent continuous wall prefabricated blocks 310 are butt jointed by an arc-shaped bolt 313, the arc-shaped bolt 313 passes through the connecting groove 314, and a grouting hole 311 and a round hole 312 are arranged between the two ends of the continuous wall prefabricated block 310, when the continuous wall prefabricated block 300 is assembled into the continuous wall 500, concrete is poured into the grouting hole 311, and a steel pipe is inserted into the round hole 312, and the steel pipe is also poured with concrete, so that the continuous wall prefabricated blocks 310 can be more firmly connected together, and the waterproof effect of the continuous wall 500 is increased. The prefabricated continuous wall prefabricated block 310 is prefabricated outside the site, assembled into the continuous wall prefabricated block 300 on site, and after the jacking system is jacked into place, the end is formed with a cast-in-place section 140 by pouring reinforced concrete, and finally an enclosed continuous wall 500 structure is formed. The continuous wall 500 is vertically layered and horizontally segmented, the upper layer is a top adjusting block, the middle and bottom layers are standard blocks, one side of the first and last continuous wall prefabricated blocks 300 is reserved with connecting steel bars, facilitating the construction connection of the cast-in-place section 140. The prefabricated continuous wall prefabricated block 300 can be prefabricated in a factory or on site, compared with the original cast-in-place construction, the quality is more controllable and more secure; the whole construction process is dry construction, the waterproofing and connection treatment between the segments of the continuous wall prefabricated block 300 are more convenient, and the quality and effect are more intuitive; the method of the continuous wall prefabricated block 300 realizes the fabricated construction of the underground continuous wall, the wall size specification and connection method can be adjusted according to the geological conditions, the construction is adjustable, and the cost is more controllable; the linking method of the wall effectively solves the problem of high vertical overall requirement of the underground continuous wall with large depth.

[0056] In addition, as Figure 10 and Figure 11As shown, the guide wall 130 is further provided with a guide device 400, which includes a portal frame 420 arranged between the two rows of guide walls 130 and a sliding member for assisting the portal frame 420 to slide, and the portal frame 420 is provided with a limiting piece 430 at a position aligned with the slot section. The guide wall 130 is used to control the pushing direction of the slot section excavation and the continuous wall precast block 300, the sliding member is used to assist the portal frame 420 to slide, and the limiting piece 430 is used to control the overall elevation of the continuous wall precast block 300. The guide wall 130 is a reinforced concrete structure, the depth of the guide wall 130 exceeds the top of the continuous wall precast block 300, and the width is determined according to the actual situation. The sliding member is composed of a prefabricated track plate and a groove rail 410, the prefabricated track plate is a cuboid reinforced concrete structure, which is placed on the guide wall and under the groove rail 410, and is hoisted and moved along the pushing direction, the groove rail 410 is processed into a groove structure by thick steel plate, and is composed of a built-in steel ball 411 and lubricating oil, and is hoisted and moved along the pushing direction. The portal frame 420 is composed of I-beams, channel steels and H-shaped steels, the bottom support is composed of two groups of I-beams welded side by side, the middle part is composed of multiple groups of I-beams welded side by side, and is vertically welded and fixed on the top support I-beam. The top is vertically welded on the middle I-beam group with the concave surface of the channel steel downward, and the equidistantly vertically welded channel steels are inside the I-beam web of the top support, and form a stable structure with the top. Two H-shaped steels are welded at the bottom of the first two transverse I-beams to form the limiting piece 430, and the length of the limiting piece 430 is the distance from the top of the continuous wall precast block 300 to the bottom of the middle I-beam. The arrangement of the guide wall 130 and the guide device 400 can control the direction and elevation of the horizontal pushing of the continuous wall precast block 300. Among them, the guide wall 130 can control the pushing direction of the continuous wall precast block 300 to be in the predetermined direction, and at the same time provide support for the groove rail 410. The sliding member reduces the resistance in the moving process of the portal frame 420, and also reduces the resistance in the pushing process, while ensuring that the moving direction of the guide device 400 in the pushing process is consistent with the continuous wall precast block 300. The guide device 400 can prevent the continuous wall precast block 300 from sinking downward to generate greater resistance by lifting the first continuous wall precast block 300, and can limit the upward floating of the continuous wall precast block 300 by the limiting piece 430, so as to achieve the purpose of controlling the elevation and reducing the resistance of the pushing direction of the underground continuous wall. Specifically, the guide wall 130 and the guide device 400 solve the problems of reducing resistance, direction and elevation control in the horizontal pushing of the assembled continuous wall precast block 300.

[0057] The embodiments of the application are described in detail above with reference to the drawings, but the application is not limited to the above embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the purpose of the application.

Claims

1. A construction method for a diaphragm wall in a foundation pit, characterized in that, Includes the following steps: S1. Set up two launching wells (110) and two receiving wells (120). The lines connecting the two launching wells (110) and the two receiving wells (120) form a rectangle. The two launching wells (110) are set diagonally in the rectangle. S2. Construct two rows of guide walls (130) between the launching well (110) and the receiving well (120); S3. Arrange a jacking system in the launching shaft (110) and produce prefabricated continuous wall blocks (310); S4. Assemble the prefabricated blocks (310) of the continuous wall into a prefabricated block (300) of the continuous wall, and carry out the construction of the continuous wall (500) from the starting well (110) to the receiving well (120). The two starting wells (110) are respectively facing different receiving wells (120) to carry out the construction of the continuous wall (500) synchronously. During construction, while excavating the trench between the two rows of guide walls (130), the prefabricated block (300) of the continuous wall is pushed forward by the jacking system until the first section of the prefabricated block (300) of the continuous wall enters the receiving well (120). S5. Reverse the orientation of the jacking system to construct the continuous wall (500) between the starting shaft (110) and the other receiving shaft (120). The two starting shafts (110) are facing different receiving shafts (120) to carry out the synchronous construction of the continuous wall (500). During construction, while excavating the trench between the two rows of guide walls (130), the jacking system is used to advance the precast blocks (300) of the continuous wall until the first precast block (300) of the continuous wall enters the receiving shaft (120). S6. After the continuous wall (500) between the launching well (110) and the receiving well (120) is pushed into place, the end cast-in-place section (140) of the two adjacent rows of continuous walls (500) is constructed. S7. Remove the jacking device in the launching well (110) and backfill soil into the launching well (110) and the receiving well (120).

2. The construction method for a diaphragm wall in a foundation pit according to claim 1, characterized in that: When constructing a diaphragm wall, after the first section of the diaphragm wall precast block (300) is assembled, it is lowered into the launching shaft (110). The advancing end of the first section of the diaphragm wall precast block (300) is equipped with a jacking head (230). After the first section of the trench is excavated, the first section of the diaphragm wall precast block (300) is pushed into the first section of the trench through the jacking system. After each section of the trench is excavated, a new section of the diaphragm wall precast block (300) is added into the launching shaft (110). The diaphragm wall (500) is formed by splicing multiple sections of the diaphragm wall precast block (300).

3. The construction method for a diaphragm wall in a foundation pit according to claim 1, characterized in that: When the precast continuous wall block (300) of the first section is close to the receiving well (120), a first slot is opened in the well wall of the receiving well (120) by means of water drilling or wire sawing. A steel structure door frame (111) for receiving the precast continuous wall block (300) of the first section is installed in the first slot. A high-pressure jet grouting pile (112) is constructed outside the outlet of the first slot.

4. The construction method for a diaphragm wall in a foundation pit according to claim 3, characterized in that: In step S3, after the jacking system is installed, a second slot is drilled on the well wall of the starting well (110) by means of a water drill or wire saw. The steel structure door frame (111) is installed around the second slot, and a high-pressure jet grouting pile (112) is constructed at the entrance of the second slot.

5. The construction method for a diaphragm wall in a foundation pit according to claim 4, characterized in that: After the continuous wall (500) between the launching well (110) and the receiving well (120) is pushed into place, grouting is performed between the steel structure door frame (111) and the continuous wall (500).

6. The construction method for a diaphragm wall in a foundation pit according to claim 1, characterized in that: The jacking system includes a three-dimensional jacking assembly (220), a sliding rail assembly (150), and a controller for controlling the three-dimensional jacking assembly (220). The controller is located outside the launching shaft (110), and a back wall (210) for installing the three-dimensional jacking assembly (220) is provided inside the launching shaft (110). The sliding rail assembly (150) is located at the bottom of the launching shaft (110) and is used to assist the sliding of the precast continuous wall block (300).

7. The construction method for a diaphragm wall in a foundation pit according to claim 6, characterized in that: The slide rail assembly (150) includes a grooved slide rail (152) and a base plate (151). The base plate (151) is made of reinforced concrete. The grooved slide rail (152) is U-shaped and fixed to the base plate (151). Steel balls (153) are laid inside the grooved slide rail (152).

8. The construction method for a diaphragm wall in a foundation pit according to claim 1, characterized in that: The side of the prefabricated continuous wall block (310) is provided with a connecting channel (314) for docking. Two adjacent prefabricated continuous wall blocks (310) are docked by an arc bolt (313). The arc bolt (313) passes through the connecting channel (314). A grouting hole (311) and a round hole (312) are provided between the two ends of the prefabricated continuous wall block (310).

9. The construction method for a diaphragm wall in a foundation pit according to claim 1, characterized in that: The guide wall (130) is also provided with a guide device (400), which includes a gantry frame (420) erected between the two rows of guide walls (130) and a sliding component for assisting the gantry frame (420) in sliding movement. The gantry frame (420) is provided with a limit member (430) aligned with the position of the groove segment.

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