Combined supporting structure for deep foundation pit of equipment utility tunnel under complex geological conditions

Abstract

The utility model provides an equipment utility tunnel deep foundation pit combined supporting structure under complex geological conditions, which comprises steel sheet piles surrounding the periphery of a foundation pit, a steel support for supporting the steel sheet piles, a steel enclosing purlin for connecting the steel support and the steel sheet piles, a support changing plate strip, a foundation cushion layer, a foundation bottom plate, an isolation material, a waterproof material and an equipment utility tunnel outer wall, the foundation bed is arranged at the bottom of a foundation pit, the support changing plate strip is arranged in the width of a fat groove between the equipment utility tunnel outer wall and the steel sheet pile, reinforcing steel bars are bound on the support changing plate strip, the isolation material is arranged between the support changing plate strip and the steel sheet pile, and the waterproof material is laid on the foundation bed and located on the outer side of the equipment utility tunnel outer wall and bent upwards. And then folding and extending to the junction with the support changing plate belt to be cut off. The reliability, the safety and the operation efficiency of the equipment utility tunnel deep foundation pit combined supporting construction under the complex geological condition are improved.

Description

Technical Field

[0001] The utility model relates to the field of building foundation pit support and foundation, in particular to a combined support structure for a foundation pit with a common trench depth for equipment under complex geological conditions. Background Art

[0002] With the continuous development of urban construction, the number of engineering projects involving large-scale ground excavation operations is increasing. In recent years, the equipment common trench, as a new type of building structure, is a modern and intensive urban public infrastructure. The equipment common trench gathers all the equipment and pipelines in the building, which can make full use of the underground space and optimize the building space. However, the equipment common trench has dense pipelines and equipment, a complex structural system, and has significant characteristics such as dangerousness, narrow and long foundation pits, and limited working space. The most critical work in its construction process is the foundation pit support system, which often requires the joint use of several foundation pit support forms to ensure the stability of the foundation pit support. According to the depth of the excavation of the equipment common trench, the commonly used foundation pit support forms include slope excavation, bored piles, steel sheet piles + steel support, etc. The selection of the equipment common trench foundation pit support system is closely related to the geological environment, construction conditions, waterproofing requirements, construction period, cost, etc.

[0003] Slope excavation is the simplest way to support the foundation pit, which can maintain the original stress state of the soil, but it is more suitable for foundation pits with shallow excavation depths. Bored piles are the most commonly used retaining structure in pile support. The construction process is simple and applicable to a wide range of strata, but its cost is higher than that of steel sheet piles. The deep foundation support structure of steel sheet piles + steel supports has shown a good application effect in deep foundation pit support. The small-locking Larsen steel sheet piles can effectively stop water, have a fast construction speed, have little impact on the environment, and have good bearing capacity. They are increasingly widely used in foundation pit support for large airports, ports, water conservancy projects, bridges and other projects. In comprehensive comparison, the deep foundation pit support structure of steel sheet piles + steel supports has more advantages.

[0004] The structural form of the equipment common trench is widely used in large-scale engineering projects. It has a complex interior and is equipped with sump pits, elevator pits and other structural measures. There are locations where the foundation pit floor is partially lowered. In addition, under complex geological conditions, if the foundation pit is excavated too deep, water will gush from the bottom of the pit. The waterproofing of the foundation pit floor is also an important task in the foundation pit support system. When the construction period and cost requirements are strict, the steel sheet pile support system is more suitable for large-scale engineering projects, but the steel support used in conjunction with it will affect the progress of the vertical construction section of the equipment common trench. It can be seen that, considering the construction period and cost, the deep foundation pit support system in the equipment common trench area under complex geological conditions needs to solve the problems of waterproofing the foundation pit floor, handling the location of the local lowering of the floor, and removing and replacing the steel support.

[0005] In the treatment of the local elevation reduction position of the equipment common trench foundation bottom plate, the conventional practice is to excavate the cushion layer with slope or build a brick membrane, and then construct the waterproof layer and bottom plate. The existing equipment common trench deep foundation pit support system design is not perfect, and there is a lack of deep foundation pit support system research that takes into account cost, construction period, construction conditions, geological complexity, etc. In related studies, the excavation depth of the deep foundation pit of the equipment common trench is usually less than 10m. For the equipment common trench with complex structural systems and geological conditions and an excavation depth greater than 10m, in addition to taking into account the above-mentioned conditions such as cost and construction period, it is also necessary to consider the stability and safety of the entire deep foundation pit support system. The local bottom plate elevation reduction treatment is carried out by using the cushion layer slope excavation or brick membrane masonry. The slope excavation is applicable to a wider range of foundation soil layers and can also be used when the height difference is large. However, in the case of complex geological conditions, certain slope protection measures need to be considered, and the cushion layer and bottom plate are at risk of collapse. Masonry brick membrane is only suitable for the case where the height difference of the foundation bottom plate is small, and it is difficult to provide effective lateral constraints on the original foundation soil. At the same time, the deep foundation slab under complex conditions often has higher waterproofing requirements. When replacing the support, the concrete force transfer belt is often cast together with the foundation slab. The outsourced waterproof material extends to the connection with the temporary enclosure, bends and turns up to the force transfer belt. There is a lack of reliable connection between the waterproof material and the structure at the temporary enclosure pile structure, and the waterproof effect is difficult to guarantee. In order to ensure the smooth construction of the vertical construction section of the equipment common trench, the concrete force transfer belt is cast together with the foundation slab. This requires waiting until the foundation slab and the concrete force transfer belt reach the required strength at the same time before the internal support can be removed, and then the vertical construction of the structure can be carried out, which delays the progress of the vertical construction of the structure. The foundation slab and the concrete force transfer belt are of the same thickness, which makes it difficult to ensure the stability of the enclosure pile structure with a longer length, and safety accidents are prone to occur. Utility Model Content

[0006] The purpose of the utility model is to provide a common trench depth foundation pit support system for equipment under complex geological conditions, taking into account factors such as cost, construction period, complex geological conditions, limited operating conditions, and foundation pit excavation depth greater than 10m, and effectively ensure the stability and safety of the steel sheet pile + steel support support system.

[0007] In order to achieve the above-mentioned purpose, the utility model provides a combined support structure for a deep foundation pit of a common trench of equipment under complex geological conditions, comprising steel sheet piles surrounding the periphery of the foundation pit, steel supports supporting the steel sheet piles, and steel purlins connecting the steel supports and the steel sheet piles, and also comprising a support plate belt, a foundation cushion, a foundation bottom plate, an isolation material, a waterproof material, and an equipment common trench outer wall. The foundation cushion is laid at the bottom of the foundation pit, the support plate belt is arranged within the width of the fertilizer trough between the equipment common trench outer wall and the steel sheet piles, steel bars are tied on the support plate belt, the isolation material is arranged between the support plate belt and the steel sheet piles, the waterproof material is laid on the foundation cushion, and the waterproof material is bent upward at the outer side of the equipment common trench outer wall, and then folded and laid to the junction with the support plate belt and cut off.

[0008] Furthermore, the top of the steel sheet pile is exposed relative to the foundation pit.

[0009] Furthermore, it also includes a steel column, which is connected to the middle part of the steel support, and the bottom end of the steel column is inserted into the bottom of the foundation pit.

[0010] Furthermore, the support plate belt is in the form of an upward-turned corbel.

[0011] Furthermore, a concrete slab belt having the same height as the foundation slab is provided between the foundation slab and the supporting plate belt, and the concrete slab belt and the supporting plate belt are provided integrally.

[0012] Furthermore, at the local reduced elevation of the foundation slab, a slope is set downward along the higher foundation slab, a reinforcement pile is arranged inside one side of the higher foundation slab, and the foundation cushion layer is arranged according to the corresponding slope.

[0013] The above solution of the utility model has the following beneficial effects:

[0014] The combined support structure for deep foundation pits with common trenches provided by the utility model under complex geological conditions integrates soil unloading and slope laying + steel sheet piles + steel support + replacement support plate belt + reinforced pile body, which can take into account factors such as cost, construction period, construction conditions, geological environment conditions, etc., and is suitable for excavation and support of deep foundation pits with common trenches for equipment with long steel sheet piles, complex geological conditions and complex structures;

[0015] The utility model unloads soil and slopes the upper part of the steel sheet pile enclosure, and adds a raised upward-turning corbel-type support plate belt at the bottom of the foundation pit, thereby reducing the inward thrust of the upper soil on the steel sheet piles, enhancing the supporting force of the steel sheet piles when the steel supports are removed, and protecting the stability of the steel sheet pile enclosure; moreover, this method can reduce the number of steel supports used from the beginning of the foundation pit excavation, reduce the time required for installation and disassembly, and provide more space for operations at the bottom of the foundation pit;

[0016] The utility model changes the construction sequence of the conventional concrete force transmission belt. After the construction of the foundation cushion layer is completed, the steel bars of the replacement support plate belt are tied and the concrete is poured. After the required strength is reached, the lower steel support can be removed. At the same time, the laying of waterproof materials on the foundation bottom plate, the steel bars of the foundation bottom plate, and the vertical steel bars can be tied, without hindering the construction of the vertical construction section of the structure. The method of casting the replacement support plate belt and the foundation bottom plate separately also provides convenience for the laying of the waterproof materials of the foundation cushion layer. The waterproof materials are laid upward along the side walls of the replacement support plate belt and are cut off at the junction, so as to avoid the conventional practice of the waterproof materials contacting with the temporary enclosure structure and turning up at the replacement support plate belt, which makes it impossible to guarantee the waterproof effect and wastes the waterproof materials.

[0017] The utility model excavates the slope downward along the higher foundation bottom plate at the local elevation reduction of the foundation bottom plate, and drives the reinforcement piles for slope protection into the higher foundation bottom plate side by using the rotary jet device, and the foundation cushion layer is also poured and constructed according to the slope. Under complex geological conditions, it can play the role of soil retaining and waterproofing, and ensure the safety and stability of the local elevation reduction position;

[0018] Other beneficial effects of the present invention will be described in detail in the subsequent specific implementation sections. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the basic composition of the foundation pit support structure in the equipment common trench area of ​​the utility model;

[0020] Figure 2 It is a schematic diagram of the arrangement of the replacement support plate belt and the waterproof material at the junction of the utility model;

[0021] Figure 3 It is a schematic diagram of the slope protection measures at the location where the elevation of the foundation bottom plate is partially lowered according to the utility model.

[0022] [Description of Reference Numerals]

[0023] 1-foundation pit; 2-steel sheet piles; 3-steel support; 4-steel purlin; 5-steel column; 6-replacement support strip; 7-foundation cushion; 8-foundation bottom plate; 9-isolation material; 10-waterproof material; 11-external wall of equipment common trench; 12-reinforcement steel bars; 13-higher foundation bottom plate; 14-lower foundation bottom plate; 15-reinforcement piles. DETAILED DESCRIPTION

[0024] In order to facilitate the understanding of the present application, the present application will be described more comprehensively with reference to the relevant drawings below. The preferred embodiments of the present application are provided in the drawings. However, the present application can be implemented in many other different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present application more thorough and comprehensive.

[0025] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0026] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0027] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0028] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0029] like Figure 1 As shown, the embodiment of the utility model provides a combined support structure for a common trench deep foundation pit of equipment under complex geological conditions, based on a narrow and deep foundation pit 1 with a depth of more than 10m, including steel sheet piles 2 surrounding the foundation pit 1, steel supports 3 supporting the steel sheet piles 2, and steel surrounding purlins 4 connecting the steel supports 3 and the steel sheet piles 2. It also includes steel columns 5. Since the excavation depth of the narrow and deep foundation pit 1 is more than 10m, in order to ensure the excavation construction efficiency of the foundation pit 1, a long steel sheet pile 2 is used as the enclosure structure of the side wall of the foundation pit 1. During construction, the steel sheet pile 2 is first driven into the soil body, and then the foundation pit 1 is excavated. At the same time, in order to reduce the thrust of the top of the steel sheet pile 2 toward the foundation pit 1 and reduce the deformation of the top of the steel sheet pile 2, the soil is unloaded and the slope is released according to a certain slope, so that the top of the steel sheet pile 2 is exposed to a certain height. The steel support 3 is horizontally arranged. As the depth of the foundation pit 1 increases step by step, the two ends of the steel support 3 are fixedly connected to the steel sheet pile 2 through the steel surrounding purlins 4 to support the steel sheet pile 2 laterally. When the steel support 3 is too long, a steel column 5 is added in the middle position, and the bottom end of the steel column 5 is inserted into the bottom of the foundation pit 1 to form a vertical support for the middle part of the steel support 3.

[0030] At the same time Figure 2As shown, the combined support structure of the deep foundation pit of the common trench of the equipment under complex geological conditions also includes a replacement support plate belt 6, a foundation cushion layer 7, a foundation bottom plate 8, an isolation material 9, a waterproof material 10, and an outer wall 11 of the common trench of the equipment. After the excavation of the foundation pit 1 is completed and the support system of the steel sheet pile 2 + steel support 3 is erected, the construction of the foundation cushion layer 7 is carried out, and the foundation cushion layer 7 is laid at the bottom of the foundation pit 1. The replacement support plate belt 6 is arranged within the width of the fertilizer trough between the outer wall 11 of the common trench of the equipment and the steel sheet pile 2, and is installed after the construction of the foundation cushion layer 7 is completed, and the steel bars 12 of the replacement support plate belt 6 are tied. The replacement support plate belt 6 adopts the form of an upturned corbel to provide more firm and reliable support for the steel sheet pile 2. The isolation material 9 is arranged between the replacement support plate belt 6 and the steel sheet pile 2 for isolation. The waterproof material 10 is continuously laid on the foundation cushion layer 7, and is laid upward on the outer side of the equipment common trench outer wall 11, and then folded and laid to the junction with the replacement support plate belt 6 and cut off, and the cut is sealed.

[0031] It should be noted that during construction, the concrete of the replacement support plate belt 6 is poured first. When the concrete reaches the required strength, the waterproof material 10 can be pasted and the steel bars 12 can be tied at the foundation bottom plate 8. When the strength of the replacement support plate belt 6 reaches the required strength, the upper steel support 3 can be removed, and the steel bars 12 of the equipment common trench outer wall can be tied and the foundation bottom plate 8 and the equipment common trench outer wall 11 can be poured. In addition, a concrete plate belt with the same height as the foundation bottom plate 8 is poured between the foundation bottom plate 8 and the replacement support plate belt 6, which is integrated with the replacement support plate belt 6 and can enhance the force transmission effect of the replacement support plate belt 6.

[0032] At the same time Figure 3 As shown, as a further improvement, in this embodiment, at the local elevation reduction of the foundation slab 8, the slope excavation is carried out downward along the higher foundation slab 13 (lower foundation slab 14), and the reinforcing piles 15 for slope protection are driven into the side of the higher foundation slab 13 by using a rotary jet device, and the foundation cushion layer 7 is also poured and constructed according to this slope. Under complex geological conditions, it can play the role of retaining soil and waterproofing, and ensure the safety and stability of the local elevation reduction position.

[0033] As described above, the solution provided by this embodiment is a composite foundation pit support system, which integrates soil unloading and slope release + steel sheet piles 2 + steel supports 3 + replacement support plate belts 6 + reinforced pile bodies 15, and can take into account factors such as cost, construction period, construction conditions, and geological environmental conditions. It is suitable for excavation and support of deep foundation pits with common trenches and equipment with long steel sheet piles 2, complex geological conditions, and complex structures.

[0034] This solution unloads soil and slopes the upper part of the steel sheet pile 2 enclosure, and adds an increased upward-turning bracket-type support plate belt 6 at the bottom of the foundation pit 1, thereby reducing the inward thrust of the upper soil on the steel sheet pile 2, enhancing the support force on the steel sheet pile 2 when the steel support 3 is removed, and protecting the stability of the steel sheet pile 2 enclosure. In addition, this solution can reduce the number of steel supports 3 used from the beginning of the excavation of the foundation pit 1, reduce the time required for installation and disassembly, and provide more space for operations at the bottom of the foundation pit 1.

[0035] This scheme changes the construction sequence of conventional concrete force transfer belts. In conventional practice, the concrete force transfer belt needs to be cast together with the foundation slab 8, and the upper support can only be removed after reaching the required strength. This will delay the binding of the steel bars 12 of the vertical wall, and sometimes may conflict with the vertical wall. After the construction of the foundation cushion layer 7 is completed, the utility model binds the steel bars 12 of the replacement support plate belt 6 and casts concrete. After reaching the required strength, the lower steel support 3 can be removed. At the same time, the waterproof material 10 on the foundation slab 8 can be laid, the steel bars 12 of the foundation slab 8 can be tied, and the vertical steel bars 12 can be tied, etc., without hindering the construction of the vertical construction section of the structure. The method of casting the replacement support plate belt 6 and the foundation slab 8 separately also provides convenience for the laying of the waterproof material 10 of the foundation cushion layer 7. The waterproof material 10 is laid upward along the side wall of the replacement support plate belt 6 and cut off at the junction, avoiding the conventional practice that the waterproof material 10 contacts the temporary enclosure structure and turns up at the replacement support plate belt 6, the waterproof effect cannot be guaranteed and the waterproof material 10 is wasted.

[0036] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0037] The above embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the application. It should be pointed out that, for a person of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A combined support structure for deep foundation pits with common trenches for equipment under complex geological conditions, characterized in that: The invention comprises steel sheet piles (2) surrounding a foundation pit (1), steel supports (3) supporting the steel sheet piles (2), and steel purlins (4) connecting the steel supports (3) and the steel sheet piles (2), and also comprises a supporting plate belt (6), a foundation cushion layer (7), a foundation bottom plate (8), an isolation material (9), a waterproof material (10), and an equipment common trench outer wall (11), wherein the foundation cushion layer (7) is arranged at the bottom of the foundation pit (1), and the supporting plate belt (6) is arranged at the equipment common trench outer wall (11). Within the width of the equipment common trench between the outer wall (11) of the equipment common trench and the steel sheet piles (2), the steel bars (12) are tied to the supporting plate belt (6), the isolation material (9) is arranged between the supporting plate belt (6) and the steel sheet piles (2), the waterproof material (10) is laid on the foundation cushion layer (7), and at the outer side of the outer wall (11) of the equipment common trench, the waterproof material (10) is bent upward, and then folded and extended to the junction with the supporting plate belt (6) and cut off.

2. The equipment common trench deep foundation pit combined support structure under complex geological conditions according to claim 1 is characterized in that: The top of the steel sheet pile (2) is exposed relative to the foundation pit (1).

3. The equipment common trench deep foundation pit combined support structure under complex geological conditions according to claim 1 is characterized in that: It also includes a steel column (5), which is connected to the middle part of the steel support (3), and the bottom end of the steel column (5) is inserted into the bottom of the foundation pit (1).

4. The equipment common trench deep foundation pit combined support structure under complex geological conditions according to claim 1 is characterized in that: The supporting plate belt (6) is in the form of an upward-turned corbel.

5. The equipment common trench deep foundation pit combined support structure under complex geological conditions according to claim 1 is characterized in that: A concrete slab belt having the same height as the foundation slab (8) is also provided between the foundation slab (8) and the supporting slab belt (6); the concrete slab belt and the supporting slab belt (6) are provided integrally.

6. The equipment common trench deep foundation pit combined support structure under complex geological conditions according to claim 1 is characterized in that: At the local elevation reduction point of the foundation slab (8), a slope is set downward along the higher foundation slab (13), a reinforcement pile body (15) is arranged inside one side of the higher foundation slab (13), and the foundation cushion layer (7) is arranged according to the corresponding slope.

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