CN219568906U - A foundation pit support structure for settlement control of connected box culverts in deep fill areas - Google Patents

Abstract

The utility model relates to a foundation pit support structure for the settlement control of a connected box culvert in a deep filling area, which comprises Larsen steel sheet piles respectively arranged at the positions of the side walls of each side of the connected box culvert foundation pit, The steel support structure inside the pit and the foundation treatment structure at the bottom of the foundation pit connected to the box culvert. It is arranged adjacent to the inner side of the Larsen steel sheet pile, and the steel support structure is connected and fixed with the upper part of the Larsen steel sheet pile. The foundation treatment structure penetrates deep soft soil and extends into the stable soil layer below the foundation pit soil. Adopting the combined support system of "Larsen steel sheet pile + steel support support structure + foundation treatment structure", the operation is simple, the construction technology is mature, the safety is high, the quality of foundation reinforcement is reliable, and the steel can be recycled, which is economical and sufficient. The advantages of green and low carbon, energy saving and emission reduction, and resource recycling have been realized.

Description

A foundation pit support structure for settlement control of connected box culverts in deep fill areas

technical field

The utility model relates to the technical field of foundation pit support, in particular to a foundation pit support structure for settlement control of connected box culverts in deep filling areas.

Background technique

Connecting box culverts, as one of the important hydraulic structures for regulating the water level of channels or lakes in cities, can significantly enhance the storage capacity of channels or lakes, and play a pivotal role in the comprehensive utilization of water resources. However, due to the impact of human activities, there are often thicker fills (such as building miscellaneous fills, plain fills, etc.) near some relatively remote lakes or channels. Due to the short accumulation period of artificial fill, the low bearing capacity of the foundation soil, and the small value of the compressive modulus, the connected box culvert may have a large settlement or settlement difference under the action of its own weight and external load, causing the box culvert to tilt , bottom plate fracture, box culvert leaking and other damages have seriously affected the normal operation of the storage function of the connected box culvert. In addition, the excavation of the foundation pit in this soft soil area is also very easy to cause the instability of the foundation pit. Engineering practice shows that when cement-soil mixing piles are used for the foundation treatment of connected box culverts, the quality of the mixing piles is often unreliable due to the large filling pores, which leads to safety hazards in the later operation of connected box culverts. At present, cast-in-place piles and pipe piles are often used to reinforce the foundation of connected box culvert foundations, while cast-in-place piles or SMW cement-soil mixing wall support structures are often used in foundation pit excavation. The above methods are costly and the construction period is relatively short. length, which greatly affects the construction efficiency and technical development of connected box culverts.

Contents of the invention

The technical problem to be solved by the utility model is to provide a foundation pit support structure for the settlement control of the connected box culvert in the deep filling area, which is used for the foundation treatment of the connected box culvert in the deep soft soil area and the deep foundation pit. Fast, safe and efficient construction provides a practical way.

The technical solution of the utility model to solve the above technical problems is as follows: a foundation pit supporting structure for the settlement control of the connected box culvert in the deep filling area, including Larsen steel plates respectively arranged at the positions of the side walls of each side of the connected box culvert foundation pit piles, the steel support structure arranged inside the foundation pit of the connected box culvert, and the foundation treatment structure arranged at the bottom of the foundation pit of the connected box culvert, the Larsen steel sheet piles are connected end to end and buried in the foundation pit soil, and the The lower end of the Larsen steel sheet pile penetrates the deep soft soil and extends into the stable soil layer below the soil of the foundation pit. The inner side of the Larsen steel sheet pile, and the steel support structure is connected and fixed to the upper part of the Larsen steel sheet pile, and the foundation treatment structure penetrates deep soft soil and extends into the stable soil layer below the foundation pit soil .

The beneficial effects of the utility model are: the foundation pit support structure of the deep filling area connected with the box culvert settlement control of the utility model adopts the combined support system of "Larsen steel sheet pile + steel support support structure + foundation treatment structure", The operation is simple, the construction technology is mature, the safety is high, the foundation reinforcement quality is reliable, and the steel can be recycled, and the economy is good, fully realizing the advantages of green low carbon, energy saving and emission reduction, and resource recycling.

On the basis of the above technical solution, the utility model can also be improved as follows:

Further: a fertilizer tank is arranged between the Larsen steel sheet pile and the connected box culvert structure, and the bottom of the fertilizer tank is backfilled with C35 plain concrete having the same thickness as the bottom plate of the connected box culvert structure, and the middle of the fertilizer tank The upper part is backfilled with C20 plain concrete, and linoleum is arranged between the Larsen steel sheet pile and the C35 plain concrete and the C20 plain concrete respectively.

The beneficial effect of the above further scheme is: by setting a fertilizer groove between the Larsen steel sheet pile and the C35 plain concrete and the C20 plain concrete respectively, and backfilling with the C20 plain concrete and the C35 plain concrete, at the same time The Larsen steel sheet pile is separated from the C35 plain concrete and the C20 plain concrete by setting the linoleum, which not only ensures the construction space for the bottom plate, side wall and roof pouring of the connected box culvert structure, but also facilitates the operation of personnel and equipment. The uniformity and compaction effect of the backfill material are ensured, so that the connected box culvert structure forms a continuous stressed whole with the soil body and the backfill material, and at the same time avoids disturbance and damage to the structure when the Larsen steel sheet pile is recovered.

Further: the steel support structure includes steel supports, frame-shaped steel waist beams and steel corbels, the steel waist beams are arranged in the foundation pit of the connected box culvert, and are adjacently arranged on the inner side of the Larsen steel sheet pile , and the steel support is arranged between the front and rear sides of the steel waist beam, and the two ends of the steel support are respectively connected to the front and rear sides of the steel waist beam, and the steel corbel is along the The steel waist beams are arranged at intervals in the length direction, and the steel corbels abut against and support the steel supports.

The beneficial effect of the above further scheme is: the steel support, the steel waist beam and the Larsen steel sheet pile are welded and connected through the steel plate, making it an integral stress system, which greatly improves the bending strength and mechanical performance of the Larsen steel sheet pile , the protective structure is firm and the supporting structure is stable, and the steel support can be stably supported by the steel corbel.

Further: the steel lumbar beam is a double I-beam lumbar beam composed of two sets of I-beams, one end face of one set of I-beams and one end face of the other set of I-beams are welded to the corresponding Larsen steel sheet pile, and form a weld foot.

The beneficial effect of the above-mentioned further scheme is: adopting double I-shaped steel lumbar beams, welding the steel lumbar beams and Larsen steel sheet piles through steel plates, making it an integral force-bearing system, its protective structure is strong, and it is convenient for the steel lumbar beams to be installed Install.

Further: the foundation treatment structure includes a plurality of high-pressure jet grouting piles, compacted clay and C20 plain concrete cushion, the plurality of high-pressure jet grouting piles are arranged at the bottom of the connected box culvert foundation pit, and the plurality of high-pressure jet grouting piles The high-pressure rotary grouting piles penetrate deep soft soil and extend into the stable soil layer below the soil of the foundation pit. A plurality of the high-pressure rotary grouting piles are arranged at even intervals, and the compacted clay is arranged at the bottom of the connected box culvert foundation pit And located above the high-pressure jet grouting pile, the C20 plain concrete cushion is laid on the compacted clay, and the C20 plain concrete cushion is located below the connected box culvert structure.

The beneficial effect of the above-mentioned further scheme is: the C20 plain concrete cushion plays the role of protecting the foundation, and at the same time has the effects of water-proof, anti-freezing, and spreading loads, and significantly improves the deformation capacity of the foundation soil of the connected box culvert structure. It can avoid the destructive effect of dynamic water pressure on the foundation soil under the action of infiltration, and play a water-proof effect. At the same time, the high-pressure rotary grouting pile sprays the cement slurry into the soil layer and mixes with the soil through the high-pressure rotating nozzle to form a continuous lapped cement reinforcement. , greatly improving the compressive modulus and bearing capacity of the foundation soil, thereby reducing the uneven settlement of the connected box culvert structure.

Further: the widths of the C20 plain concrete cushion and the compacted clay are consistent with the overhang dimensions of the foundation structure of the connected box culvert structure, and the compaction coefficient of the compacted clay is not less than 0.94.

Further: the foundation pit support structure for the settlement control of the connected box culvert in the deep filling area also includes an intercepting ditch, and the intercepting ditch is arranged on the surface of the top of the foundation pit on both sides of the connected box culvert foundation pit.

The beneficial effects of the above further solution are: by setting the intercepting ditch, surface water, rainwater and temporary construction water can be eliminated, the erosion of the side wall of the foundation pit is reduced, and the stability of the support system is significantly improved.

Description of drawings

Fig. 1 is the structure schematic diagram of the foundation pit supporting structure of the settlement control of the connected box culvert in the deep filling area of an embodiment of the utility model;

Fig. 2 is the A-A sectional structural schematic diagram of Fig. 1;

Fig. 3 is a large sample diagram of the connection between Larsen steel sheet pile and steel support according to an embodiment of the present invention;

Fig. 4 is a schematic diagram of a Larsen steel sheet pile according to an embodiment of the present invention.

In the accompanying drawings, the list of parts represented by each label is as follows:

1. Foundation pit soil, 2. Larsen steel sheet pile, 3. Steel waist beam, 4. Connected box culvert structure, 5. Steel support, 6. High-pressure rotary grouting pile, 7. Foundation pit top, 8. Water intercepting ditch , 9, C20 plain concrete, 10, linoleum, 11, C35 plain concrete, 12, C20 plain concrete cushion, 13, compacted clay, 14, steel plate, 15, welding foot, 16, steel corbel.

Detailed ways

The principles and features of the present utility model are described below in conjunction with the accompanying drawings, and the examples given are only used to explain the utility model, and are not used to limit the scope of the utility model.

As shown in Figures 1 to 4, a foundation pit support structure for the settlement control of a connected box culvert in a deep fill area includes Larsen steel sheet piles 2, The steel supporting support structure arranged inside the foundation pit of the connected box culvert and the foundation treatment structure arranged at the bottom of the foundation pit of the connected box culvert, the Larsen steel sheet piles 2 are connected end to end side by side and buried in the foundation pit soil 1, and The lower end of the Larsen steel sheet pile 2 penetrates the deep soft soil and extends into the stable soil layer below the foundation pit soil 1, and the steel support structure is arranged in the connected box culvert foundation pit and adjacent to it It is arranged inside the Larsen steel sheet pile 2, and the steel support structure is connected and fixed to the upper part of the Larsen steel sheet pile 2, and the foundation treatment structure penetrates deep soft soil and extends into the foundation pit soil 1 in the stable soil below.

The foundation pit support structure of the utility model for the settlement control of the connected box culvert in the deep filling area adopts the combined support system of "Larsen steel sheet pile + steel support support structure + foundation treatment structure", which is easy to operate, mature in construction technology, and safe. High reliability, reliable quality of foundation reinforcement, and recyclable steel, good economy, fully realize the advantages of green low carbon, energy saving and emission reduction, and resource recycling.

In one or more embodiments of the present utility model, the Larsen steel sheet pile 2 adopts FSP-IV type, with a wall thickness of 15.5 mm, a cross-sectional area of 96.99 cm ² per piece, and a secondary moment of 4670 cm ⁴ per piece. 38600cm ⁴ per meter, section modulus 362cm ³ per piece, 2270cm ³ per meter.

In one or more embodiments of the present utility model, a fertilizer groove is arranged between the Larsen steel sheet pile 2 and the connected box culvert structure 4, the width of the fertilizer groove is about 0.8 meters, and the bottom of the fertilizer groove is backfilled with C35 plain concrete 11 with the same bottom plate thickness of the connected box culvert structure 4, C20 plain concrete 9 backfilled in the middle and upper part of the fertilizer tank, and the Larsen steel sheet pile 2 is connected with the C35 plain concrete 11 and C20 plain concrete 9 respectively. Linoleum 10 is arranged between the concrete 9 . By arranging fertilizer grooves between the Larsen steel sheet pile 2 and the C35 plain concrete 11 and the C20 plain concrete 9 respectively, and using the C20 plain concrete and the C35 plain concrete to backfill, at the same time, the Larsen steel plate The pile 2 is separated from the C35 plain concrete 11 and the C20 plain concrete 9 by setting the linoleum 10 respectively, which not only ensures the construction space for the bottom plate, side wall and roof pouring of the connected box culvert structure 4, but also facilitates the operation of personnel and equipment. The uniformity and compaction effect of the backfill material are ensured, so that the connected box culvert structure 4 forms a continuous stressed whole with the soil body and the backfill material, and at the same time avoids disturbance and damage to the structure when the Larsen steel sheet pile 2 is recovered.

In one or more embodiments of the present utility model, the steel support structure includes a steel support 5, a frame-shaped steel waist beam 3 and a steel corbel 16, and the steel waist beam 3 is arranged in the connecting box In the culvert foundation pit, and adjacent to the inner side of the Larsen steel sheet pile 2, and the steel support 5 is arranged between the front and rear sides of the steel waist beam 3, and the two ends of the steel support 5 are respectively Correspondingly connected to the front and rear sides of the steel waist beam 3, the steel brackets 16 are arranged at intervals along the length direction of the steel waist beam 3, and the steel brackets 16 abut against the steel support 5 and The steel support 5 is supported. The steel support 5, the steel waist beam 3 and the Larsen steel sheet pile 2 are welded and connected through the steel plate, making it an integral stress system, which greatly improves the bending strength and mechanical performance of the Larsen steel sheet pile 2, and its protective structure It is strong, and the supporting structure is stable, and the steel support 5 can be stably supported by the steel corbel 16 .

Specifically, in one or more embodiments of the present utility model, the steel waist beam 3 is a double I-shaped steel waist beam composed of two sets of I-beams, wherein one end face of one set of I-beams and the other One end face of a group of I-beams is welded to the corresponding Larsen steel sheet pile 2 through a steel plate 14 to form a welding leg 15 . Double I-shaped steel waist beams are adopted, and steel waist beams 3 and Larsen steel sheet piles 2 are welded through steel plates to form an integral force-bearing system. The protective structure is strong and the installation of steel waist beams is convenient.

In the embodiment of the present utility model, the steel support 5 adopts a spiral steel pipe with a diameter of 426 mm and a wall thickness of 10 mm.

In an embodiment of the present utility model, the steel plate 14 is a 500mm×500mm×12mm steel plate.

In the embodiment of the present utility model, the steel corbel 16 adopts double steel plates of 350mm×350mm×12mm.

In one or more embodiments of the present utility model, the foundation treatment structure includes a plurality of high-pressure jet grouting piles 6, compacted clay 13 and C20 plain concrete cushion 12, and a plurality of high-pressure jet grouting piles 6 are arranged on The bottom of the connected box culvert foundation pit, and the plurality of high-pressure jet grouting piles 6 penetrate deep soft soil and extend into the stable soil layer below the foundation pit soil 1, and the plurality of high-pressure jet grouting piles 6 are evenly spaced, the compacted clay 13 is arranged at the bottom of the connected box culvert foundation pit and above the high-pressure jet grouting pile 6, the C20 plain concrete cushion 12 is laid on the compacted clay 13, and The C20 plain concrete cushion 12 is located below the connected box culvert structure 4 . The C20 plain concrete cushion layer 12 plays the role of protecting the foundation, and also has the effects of water insulation, antifreeze, and spreading load, which significantly improves the deformation capacity of the foundation soil of the connected box culvert structure. The use of compacted clay 13 can avoid the impact of seepage The destructive effect of water pressure on the foundation soil plays a water-proof effect, and at the same time acts as a cushion layer, which can adjust the load sharing of piles and soil, and give full play to the mutual effect of piles and soil between piles, so that the foundation can achieve coordinated deformation. At the same time, the high-pressure rotary grouting pile 6 sprays the cement slurry into the soil layer and mixes with the soil through the high-pressure rotating nozzle to form a continuous lapped cement reinforcement, which greatly improves the compression modulus and bearing capacity of the foundation soil, thereby reducing the number of connected box culverts. Uneven settlement of structures.

Optionally, in one or more embodiments of the present utility model, the widths of the C20 plain concrete cushion layer 12 and the compacted clay 13 are consistent with the overhang dimensions of the basic structure of the connected box culvert structure 4, and The compaction coefficient of the compacted clay 13 is not less than 0.94 (light compaction). Here, the C20 plain concrete cushion layer 12 has a thickness of 10 cm, and the compacted clay 13 has a thickness of 30 cm.

In the embodiment of the present utility model, the 6 pile diameters of the high-pressure rotary grouting piles are 500 mm, the vertical and horizontal distances of the high-pressure rotary grouting piles 6 are 1.2 m, and the cement strength grade used is not less than 42.5 MPa. The high-pressure rotary grouting piles The reference cement content of the 6 piles is about 35%, and the cement content in each cubic meter of stirred soil is about 630kg. The depth of the high-pressure rotary grouting pile 6 entering the stable soil layer is not less than 1.2m.

Optionally, in one or more embodiments of the present utility model, the foundation pit support structure for the settlement control of the deep filling area connected to the box culvert further includes an intercepting ditch 8, and the intercepting ditch 8 is arranged at The surface of the top 7 of the foundation pit on both sides of the foundation pit connected with the box culvert. By setting the intercepting ditch 8, surface accumulated water, rainwater and temporary construction water can be eliminated, the erosion of the side wall of the foundation pit is reduced, and the stability of the supporting system is significantly improved. Here, the size of the intercepting ditch 8 is 300mm×300mm.

The steel plate material used in the utility model is Q235 steel.

The specific practical steps of the foundation pit supporting structure controlled by the settlement of the connected box culvert in the deep filling area of the present invention are as follows:

Step 1: Site clearing, leveling, pipeline relocation and site enclosure: Before construction, the necessary clearing work should be carried out, the gravel in the miscellaneous fill or plain fill should be cleaned, and the surface water should be drained before construction. Fence the affected area to ensure safety;

Step 2: Larsen steel sheet pile 2 construction: Larsen steel sheet pile 2 needs to be brushed with anti-friction agent before insertion. The plane layout of Larsen steel sheet pile 2 should keep the axis straight and smooth, and the crawler hydraulic pile driver is used for construction. The construction should ensure that the piles are interlocked, the pile position deviation is not greater than 50mm, the pile top elevation deviation is not greater than 100mm, and the vertical deviation is not greater than 0.5%;

Step 3: Excavation of foundation pit soil 1 and construction of steel support 5: Use mechanical excavation for foundation pit soil 1. When the foundation pit is excavated to 0.5m below the design level of steel support 5, the excavation must be stopped, and steel supports should be installed in time 5. The steel support 5 is set on the steel waist beam 3. After the support is erected, the stability of the support should be checked and confirmed, and the excavation can only be continued to the bottom of the foundation pit after it is safe;

Step 4: backfill the compacted clay 13, and perform compaction, and then construct the high-pressure rotary grouting pile 6;

Step 5: The C20 plain concrete cushion 12 is laid after the construction of the high-pressure rotary grouting pile 6 is completed and the inspection is qualified;

Step 6: When the C20 plain concrete cushion layer 12 reaches 100% of the design strength, construct the connected box culvert bottom plate, side wall and roof structure;

Step 7: After the construction of the connected box culvert structure 4 is completed and the design strength reaches 100%, the foundation pit is backfilled and the steel support 5 is recovered, and the soil can only be backfilled to 0.5m below the first steel support 5 Remove the steel support 5.

Step 8: Recycling of Larsen steel sheet pile 2: Use the static method to pull out Larsen steel sheet pile 2 at intervals with a distance of not less than 2.0m. The gaps left by the pulled piles should be filled with sand in time. When the sand filling is not ideal, 1 can be used instead. :1 Cement mortar filling, the cement is made of ordinary Portland cement with a strength grade of not less than 42.5MPa, the grouting pressure is not greater than 0.1MPa, the grouting slurry should be applied with quick-setting agent, and the Larsen steel sheet pile is completed 2 recycling work.

The above descriptions are only preferred embodiments of the present utility model, and are not intended to limit the present utility model. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present utility model shall be included in this utility model. within the scope of protection of utility models.

Claims (7)

1. A foundation pit support structure for the settlement control of connected box culverts in deep filling areas, characterized in that it includes Larsen steel sheet piles (2) respectively arranged at the positions of the side walls of each side of the connected box culvert foundation pit, The steel supporting support structure inside the foundation pit of the connected box culvert and the foundation treatment structure at the bottom of the foundation pit of the connected box culvert are arranged, and the Larsen steel sheet piles (2) are connected end to end side by side and buried in the foundation pit soil (1) and the lower end of the Larsen steel sheet pile (2) penetrates the deep soft soil and extends into the stable soil layer below the foundation pit soil (1), and the steel support structure is arranged in the connecting box In the culvert foundation pit, it is adjacent to the inner side of the Larsen steel sheet pile (2), and the steel support structure is connected and fixed to the upper part of the Larsen steel sheet pile (2), and the foundation treatment structure penetrates deep The soft soil extends into the stable soil layer below the foundation pit soil (1). 2. The foundation pit support structure for the settlement control of the connected box culvert in the deep filling area according to claim 1, characterized in that: the Larsen steel sheet pile (2) and the connected box culvert structure (4) are provided with A fertilizer tank, the bottom of the fertilizer tank is backfilled with C35 plain concrete (11) having the same thickness as the bottom plate of the connected box culvert structure (4), and the middle and upper part of the fertilizer tank is backfilled with C20 plain concrete (9), and Linoleum (10) is arranged between the Larsen steel sheet pile (2) and the C35 plain concrete (11) and the C20 plain concrete (9). 3. The foundation pit support structure for the settlement control of the connected box culvert in the deep fill area according to claim 1, characterized in that: the steel support support structure comprises steel supports (5), frame-shaped steel waist beams ( 3) and a steel corbel (16), the steel waist beam (3) is arranged in the foundation pit of the connecting box culvert, and is adjacently arranged on the inner side of the Larsen steel sheet pile (2), and the steel support (5) arranged between the front and rear sides of the steel waist beam (3), and the two ends of the steel support (5) are respectively connected to the front and rear sides of the steel waist beam (3), and the Steel corbels (16) are arranged at intervals along the length direction of the steel waist beam (3), and the steel corbels (16) abut against the steel support (5) and support the steel support (5) . 4. The foundation pit support structure for settlement control of connected box culverts in deep fill areas according to claim 3, characterized in that: the steel waist beam (3) is a double-combined I-shaped beam composed of two sets of I-shaped steels Steel waist beams, one end face of one group of I-beams and one end face of another group of I-beams are welded to the corresponding Larsen steel sheet piles (2) through steel plates. 5. The foundation pit support structure for the settlement control of connected box culverts in deep fill areas according to claim 1, characterized in that: the foundation treatment structure includes a plurality of high-pressure jet grouting piles (6), compacted clay (13 ) and C20 plain concrete cushion (12), a plurality of high-pressure jet grouting piles (6) are arranged at the bottom of the connected box culvert foundation pit, and the plurality of high-pressure jet grouting piles (6) penetrate deep The soft soil extends into the stable soil layer below the foundation pit soil (1), a plurality of high-pressure jet grouting piles (6) are evenly spaced, and the compacted clay (13) is arranged in the connected box culvert foundation pit The bottom is located above the high-pressure rotary grouting pile (6), the C20 plain concrete cushion (12) is laid on the compacted clay (13), and the C20 plain concrete cushion (12) is located at the connected Below the box culvert structure (4). 6. The foundation pit support structure for the settlement control of the connected box culvert in the deep filling area according to claim 5, characterized in that: the width of the C20 plain concrete cushion (12) and the compacted clay (13) are both the same as The base structure of the connected box culvert structure (4) has the same overhang size, and the compaction coefficient of the compacted clay (13) is not less than 0.94. 7. The foundation pit supporting structure for the settlement control of connected box culverts in deep fill areas according to any one of claims 1-6, characterized in that: it also includes an intercepting ditch (8), and the intercepting ditch (8 ) is arranged on the surface of the foundation pit top (7) on both sides of the connected box culvert foundation pit.