Construction method of small-size continuous corner auxiliary diaphragm wall

Abstract

The invention discloses a construction method of a small-size continuous corner auxiliary diaphragm wall, the continuous corner auxiliary diaphragm wall comprises a plurality of unit groove sections which are connected end to end, each unit groove section comprises two straight line sections and a middle section connected between the two straight line sections, and the length of the middle section is smaller than the width of a grab bucket of a trenching machine. The construction method comprises the following steps of: lofting a side line of a gripping groove of the diaphragm wall; processing and manufacturing an underground diaphragm wall reinforcement cage and installing a steel plate; underground diaphragm wall grooving construction is carried out; constructing a steel plate rear support; the problems that a conventional small-size continuous corner amplitude diaphragm wall expands and excavates outwards, occupies pipelines and uses land outside the pipelines are effectively solved, concrete wall columns formed by pouring during internal expansion are effectively avoided, on one hand, raw material waste and machinery and manpower needed by chiseling in the later period are reduced, and the construction cost is reduced; and during later excavation, the auxiliary structure side wall can be constructed only by excavating the backfilled broken stones, so that the construction period is effectively shortened, and the method has high popularization value.

Description

Technical Field

[0001] The invention relates to the technical field of building construction, and in particular to a construction method for a small-size continuous corner auxiliary ground-connected wall. Background Art

[0002] With the development of urbanization, the radiation of urban rail transit network has been further expanded to cover new and old urban areas. Especially for old urban areas, the blue line review of urban construction land has become more stringent, and the design of underground stations is also required to be more flexible, which not only ensures the surplus of use space, but also reduces the building limit as much as possible. Therefore, in the design process of underground stations, especially the design of auxiliary entrances and exits, because they are often located at intersections and there are many important buildings nearby, the edge lines of the enclosure structure change frequently. The special-shaped ground-connected walls have the characteristics of many shapes and small sizes. How to ensure the quality and quantity of the construction enclosure structure without occupying the land outside the blue line is a major difficulty in construction control.

[0003] Traditionally, punching drills are used to drill special-shaped ground-connected walls of various shapes and small sizes. However, the above drilling method has the disadvantages of uneven drilling surface, which affects the visual effect and has poor anti-leakage effect. In addition, during pouring, due to the fluidity of concrete during pouring, concrete wall columns will be formed in the inner expansion part, which need to be chiseled out during the later construction of the side walls of the auxiliary structure, increasing the construction cost. Summary of the invention

[0004] In order to overcome the defects existing in the prior art, the present invention provides a construction method for a small-sized continuous corner auxiliary ground-connected wall, which effectively solves the problem of outward expansion of conventional small-sized continuous corner ground-connected walls, squeezing out pipelines and land outside the lines, and effectively avoids the concrete wall columns formed by pouring during inward expansion.

[0005] In order to achieve the above object, the present invention provides a construction method of a small-size continuous corner auxiliary ground diaphragm wall, wherein the continuous corner auxiliary ground diaphragm wall comprises a plurality of unit slot segments connected end to end, each unit slot segment comprises two straight segments and a middle segment connected between the two straight segments, and the length of the middle segment is less than the grab width of a slotting machine, characterized in that the construction method comprises the following steps:

[0006] According to the design requirements, the ground connection wall edge line and ground connection wall grab groove range of the continuous corner auxiliary ground connection wall shall be set out and marked;

[0007] A plurality of ground-connected wall steel cages corresponding to different unit slot sections are manufactured respectively, and the plurality of ground-connected wall steel cages are fixedly connected in sequence;

[0008] A steel plate is placed on the side of the ground-connected wall reinforcement cage corresponding to the middle section along the length direction and located inside the foundation pit, and the steel plate is fixedly connected to the horizontal reinforcement of the corresponding ground-connected wall reinforcement cage through a plurality of U-shaped reinforcements to form a whole;

[0009] Use a trenching machine to dig the ground-connected wall groove along the marked ground-connected wall edge line and the range of the ground-connected wall groove to form a slot hole, and expand the middle section inward to the inside of the foundation pit to form an inward expansion part;

[0010] The corresponding ground-connected wall reinforcement cages in different unit slot sections are hoisted respectively, and support members are set at the inner expansion part to support the steel plate;

[0011] The inner expansion part is backfilled, and after backfilling, the ground-connected wall concrete is poured for different unit slot sections.

[0012] Preferably, when the middle section is expanded inwardly toward the inside of the foundation pit to form an inwardly expanded portion, the width of the inwardly expanded portion is the width of the grab bucket of the trenching machine minus the length of the middle section.

[0013] Preferably, when a support member is provided at the inner expansion portion to support the steel plate, the setting method includes:

[0014] The corner points on both sides of the inner expansion part along the width direction of the groove section are drilled by bite drilling to form a slot;

[0015] Iron wires are used to fix several steel pipes arranged at intervals into a ladder shape and drilled into the formed slots.

[0016] Preferably, when a trenching machine is used to excavate the ground anchor wall groove along the marked ground anchor wall edge line and the range of the ground anchor wall groove to form a slot hole, the excavation order of each unit trench section is to first excavate the straight sections at both ends of the trench section and then excavate the middle section between the straight sections.

[0017] Preferably, before pouring the ground-connected wall concrete for different unit trench sections after backfilling, the installation arrangement of the casting conduit is carried out according to the installation spacing required by the design, wherein the horizontal arrangement distance of the conduit is ≤3m, the distance between the conduit and the end of the trench section is ≤1.5m, and the distance between the bottom of the conduit and the bottom of the trench is in the range of 0.3m to 0.5m.

[0018] Due to the adoption of the above technical solution, the present invention has the following beneficial effects:

[0019] It effectively solves the problem of conventional small-sized continuous corner ground-connected walls digging outward, squeezing out pipelines and land outside the lines, and can also effectively avoid the concrete wall columns formed when pouring inward. On the one hand, it reduces the waste of raw materials and the mechanical labor required for later chiseling, reducing construction costs. At the same time, during the later excavation, only the backfill gravel needs to be dug out to construct the side wall of the auxiliary structure, which can effectively save construction time compared with the traditional method that requires chiseling. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0021] Figure 1 It is a cross-sectional view of the ground-connected wall reinforcement cage in an embodiment of the present invention.

[0022] Figure 2 It is a schematic diagram of the connection between the ground-connected wall reinforcement cage and the steel plate in an embodiment of the present invention.

[0023] Figure 3 It is a schematic diagram of the inner expansion of the middle section in an embodiment of the present invention.

[0024] Figure 4 Schematic diagram of the support member arrangement in an embodiment of the present invention.

[0025] The corresponding relationship of the numbers in the accompanying drawings is as follows:

[0026] 1-I-beam; 2-ground anchor wall reinforcement cage; 3-steel plate; 5-U-shaped reinforcement; 6-inward expansion part; 7-slot; 8-straight section; 9-middle section; 10-slot; 11-steel joint. DETAILED DESCRIPTION

[0027] The specific embodiments of the present invention are further described below in conjunction with the accompanying drawings. It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0028] See also Figures 1 to 4 As shown, an embodiment of the present invention provides a construction method for a small-size continuous corner auxiliary ground-connected wall. In this embodiment, the continuous corner auxiliary ground-connected wall includes a plurality of unit slot segments connected end to end, each unit slot segment includes two straight segments 8 and a middle segment 9 connected between the two straight segments 8, and the length of the middle segment 9 is less than the grab width of the slotting machine. The construction method includes the following steps:

[0029] According to the design requirements, the ground connection wall edge line and ground connection wall grab groove range of the continuous corner auxiliary ground connection wall shall be set out and marked;

[0030] A plurality of ground-connected wall reinforcement cages 2 corresponding to different unit slot sections are respectively manufactured, and the plurality of ground-connected wall reinforcement cages 2 are fixedly connected in sequence;

[0031] A steel plate 3 is placed on the side of the ground-connected wall reinforcement cage 2 corresponding to the middle section 9 along the length direction and located inside the foundation pit, and the steel plate 3 is fixedly connected to the horizontal reinforcement of the corresponding ground-connected wall reinforcement cage 2 through a plurality of U-shaped reinforcements 5 to form a whole;

[0032] A trenching machine is used to dig the ground-connecting wall groove along the marked ground-connecting wall edge line and the range of the ground-connecting wall groove to form a slot hole, and the middle section 9 is expanded inwardly toward the inside of the foundation pit to form an inward expansion part 6;

[0033] The corresponding ground-connected wall reinforcement cages 2 in different unit slot sections are hoisted respectively, and support members are arranged at the inner expansion part 6 to support the steel plate 3;

[0034] The inner expansion part 6 is backfilled, and after backfilling, the ground-connected wall concrete is poured for different unit slot sections.

[0035] Furthermore, when the middle section 9 is expanded inwardly toward the inside of the foundation pit to form the inner expansion part 6, the width of the inner expansion part 6 is the grab width of the troughing machine minus the length of the middle section 9. It should be noted that the grab width of a conventional troughing machine is 2.8m wide, and the length of the middle section 9 is defined as B (B<2.8m). In this embodiment, the width of the inner expansion part 6 is (2.8-B)m.

[0036] Furthermore, when the slotting machine is used to dig the ground-connected wall grab groove along the marked ground-connected wall edge line and the range of the ground-connected wall grab groove to form a slot hole, the digging order of each unit slot section is to first dig the straight segments 8 at both ends of the slot segment, and then dig the middle segment 9 between the straight segments 8. It should be noted that the slotting machine equipment in this embodiment is equipped with a verticality display instrument and an automatic deviation correction device, which can measure and correct as the digging progresses, and can ensure the verticality requirements of the slot end. When the grab bucket digs the slot, the slot hole must be vertical, and the grab bucket digs the slot under a state of balanced soil resistance. It is required that the bucket teeth on both sides of the grab bucket are eaten in the solid soil or the bucket teeth on both sides of the grab bucket fall into the hollow. It is prohibited for the grab bucket teeth to eat in the solid soil on one side and fall in the hollow on the other side. Because the length of the middle segment 9 is less than the width of the grab bucket, the grab bucket can cover the middle segment 9 for digging, and at the same time, the grab bucket can make the force balanced, effectively correct the deviation, and ensure the verticality of the slot.

[0037] See also Figure 1 and Figure 2 As shown, in this embodiment, the steel cage is processed in the following order: laying the lower row of horizontal steel bars → laying the lower row of longitudinal main bars and reinforcements, and welding them firmly → welding the bottom protective layer pads → welding the middle trusses, middle reinforcement bars, and additional reinforcements at hanging points → lower row of scissor bars → welding the upper row of transverse frame steel bars → upper row of longitudinal main bars → upper horizontal steel bars → upper row of scissor bars → upper hanging point bars → welding additional reinforcements and upper row of protective layer pads.

[0038] Furthermore, the ground-connected wall steel cage of each unit slot section is hoisted as a whole at one time, and the length of the processing platform is 300mm shorter than the length of the steel cage at each end. The width is 150mm wider than the width of the steel cage on each side. On the flat hardened ground, No. 12 I-beams 1 are evenly laid in the length direction of the steel cage with a spacing of 1.0m. The two ends of the I-beams 1 are connected to form a whole with a full-length Φ18 steel bar on the top and bottom, and the height difference of the top surface of the I-beam 1 is less than 20mm. Before production, the position of the bottom distribution reinforcement is pre-painted on the top of the I-beam 1 with red paint, and then the bottom steel mesh is laid. After all the steel bars are spot welded, the frame reinforcement is set, and then the upper steel mesh is laid. After the steel cage is completed, the inside and outside; the upper end and the lower end are marked, and the elevation control points for controlling the elevation of the steel cage are set. The two ends of each unit slot section are closed with steel joints 11 to prevent leakage.

[0039] Furthermore, in this embodiment, the U-shaped rib 5 is made of C20 steel bars, which are bent into a size of 1+(B-0.1)+1m. The two ends of the U-shaped rib 5 are welded to the horizontal bars of the ground-connected wall steel cage, and the welding adopts single-sided welding of not less than 10d. The middle part of the U-shaped rib 5 is welded to the steel plate 3. The thickness of the steel plate 3 is 3mm, and the width of the steel plate is slightly smaller than the thickness of the ground-connected wall. The steel plate 3 and the U-shaped rib 5 are welded on one side.

[0040] Please refer to the figure Figure 3 and 4 As shown, when a support member is provided on the inner expansion part 6 to support the steel plate 2, the setting method includes:

[0041] The corner points of the inner expansion part 6 on both sides of the groove width direction are drilled by bite drilling to form a slot 10;

[0042] Iron wires are used to fix several steel pipes arranged at intervals into a ladder shape and drilled into the formed slots 10. It should be noted that in this embodiment, a down-the-hole drill is used, and a drill rod with a diameter of φ50mm is used for engagement drilling, and finally a slot 10 with a length of about 15cm and a width of about 5cm is formed. The steel pipe specification is about 80cm long (taking a 0.6m thick ground-connected wall as an example), with a diameter of 48mm, and is arranged at intervals of 5m.

[0043] It should be noted that, in the present embodiment, backfilling the inner expansion part 6 can prevent the concrete from being squeezed out from the bottom of the steel plate 3 and surging upward when pouring concrete, and when backfilling, the bottom 50 cm is first backfilled with clay, and the rest is backfilled with sand and gravel. During the later excavation, it is only necessary to dig out the backfill gravel and construct the side wall of the auxiliary structure, and a 3 cm protective layer is set on the side of the structural side wall facing the ground-connected wall, which will not affect its construction.

[0044] Before pouring the ground-anchored wall concrete for different unit trench sections after backfilling, the conduit shall be installed and arranged according to the installation spacing required by the design. The horizontal arrangement distance of the conduit is ≤3m, and the distance between the conduit and the end of the trench section is ≤1.5m. The conduit is hoisted into the trench by a crane for connection. The distance between the bottom of the conduit and the bottom of the trench is 0.3m to 0.5m. The conduit shall be subjected to a watertightness test before use.

[0045] Furthermore, the concrete pouring lifting frame hangs the concrete hopper and lifts the conduit through the concrete hopper. The concrete is directly fed into the hopper for pouring by a concrete delivery truck, and an inflatable rubber ball plug is used to open the pipe. During the pouring process, the conduit should always be buried in the concrete for 2m to 6m. The minimum burial depth shall not be less than 1.5m (the conduit of the first tank of concrete is 300mm to 500mm from the bottom of the trench, and the buried depth of the conduit after the first tank of concrete should be greater than 500mm). Concrete pouring should be carried out continuously, and the rising speed of the concrete surface shall not be less than 3m / h to 5m / h, and the longest allowable interval time is 20min to 30min. During the pouring process, the rising height of the concrete surface is measured every 30min to ensure accurate and timely pipe pulling.

[0046] The embodiments of the present invention are described in detail above with reference to the accompanying drawings, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions and variations of these embodiments are made without departing from the principles and spirit of the present invention, and still fall within the scope of protection of the present invention.

Claims

1. A construction method for a small-size continuous corner auxiliary ground diaphragm wall, wherein the continuous corner auxiliary ground diaphragm wall comprises a plurality of unit slot segments connected end to end, each unit slot segment comprises two straight segments and an intermediate segment connected between the two straight segments, and the length of the intermediate segment is less than the grab width of a slotting machine, characterized in that: The construction method includes the following steps: According to the design requirements, the ground connection wall edge line and ground connection wall grab groove range of the continuous corner auxiliary ground connection wall shall be set out and marked; A plurality of ground-connected wall steel cages corresponding to different unit slot sections are manufactured respectively, and the plurality of ground-connected wall steel cages are fixedly connected in sequence; A steel plate is placed on the side of the ground-connected wall reinforcement cage corresponding to the middle section along the length direction and located inside the foundation pit, and the steel plate is fixedly connected to the horizontal reinforcement of the corresponding ground-connected wall reinforcement cage through a plurality of U-shaped reinforcements to form a whole; Use a trenching machine to dig the ground-connected wall groove along the marked ground-connected wall edge line and the range of the ground-connected wall groove to form a slot hole, and expand the middle section inward to the inside of the foundation pit to form an inward expansion part; The corresponding ground-connected wall reinforcement cages in different unit slot sections are hoisted respectively, and support members are set at the inner expansion part to support the steel plate; The inner expansion part is backfilled, and after backfilling, the ground-connected wall concrete is poured for different unit slot sections.

2. The small-size continuous corner auxiliary ground-connected wall construction method according to claim 1, characterized in that: When the middle section is expanded inwardly toward the inside of the foundation pit to form an inner expanded portion, the width of the inner expanded portion is the width of the grab bucket of the trenching machine minus the length of the middle section.

3. The small-size continuous corner auxiliary ground-connected wall construction method according to claim 1, characterized in that: When a support member is provided at the inner expansion portion to support the steel plate, the setting method includes: The corner points on both sides of the inner expansion part along the width direction of the groove section are drilled by bite drilling to form a slot; Iron wires are used to fix several steel pipes arranged at intervals into a ladder shape and drilled into the formed slots.

4. The small-size continuous corner auxiliary ground-connected wall construction method according to claim 1, characterized in that: When a trenching machine is used to excavate the ground anchor wall groove along the marked ground anchor wall edge line and the range of the ground anchor wall groove to form a slot hole, the excavation order of each unit trench section is to first excavate the straight sections at both ends of the trench section and then excavate the middle section between the straight sections.

5. The small-size continuous corner auxiliary ground-connected wall construction method according to claim 1, characterized in that: Before pouring the ground-anchored wall concrete for different unit trench sections after backfilling, the installation arrangement of the pouring conduit shall be carried out according to the installation spacing required by the design, wherein the horizontal arrangement distance of the conduit is ≤3m, the distance between the conduit and the end of the trench section is ≤1.5m, and the distance between the bottom of the conduit and the bottom of the trench is in the range of 0.3m to 0.5m.

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