Foundation pit support structure under weathered rock geological layer limited space
By constructing retaining holes for the foundation pit under the weathered rock geological layer and filling them with backfill material and Larssen steel sheet piles, combined with a horizontal water-stop curtain to form a composite structure of sheet wall water-stop, the problem of foundation pit retaining with limited operating space is solved, achieving high-strength, low-deformation foundation pit retaining, ensuring construction safety and water-stopping effect.
Patent Information
- Application Number
- CN202422974265.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-03
- Publication Date
- 2025-10-31
- Estimated Expiration
- 2034-12-03
AI Technical Summary
When the distance to existing structures is small and the operating space is limited, traditional deep foundation pit construction cannot carry out the construction of foundation pit retaining structures, especially when the foundation pit retaining structures cannot be effectively constructed under weathered rock geological layers.
The foundation pit retaining holes are constructed by passing through the weathered rock geological layer along the edge of the foundation pit. Larssen steel sheet piles are inserted and backfill material is filled in. The Larssen steel sheet piles are fixed on both sides by cement mortar and undisturbed soil. Combined with a horizontal water-stop curtain, a composite structure of sheet wall water-stopping is formed to improve the stability and water-stopping effect of the retaining structure.
To achieve high-strength, low-deformation foundation pit retaining structure construction in confined spaces, prevent groundwater leakage, ensure foundation pit construction safety, avoid collapse risks, and provide excellent construction conditions.
Smart Images
Figure CN223497179U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of foundation pit retaining engineering technology, and in particular to a foundation pit retaining structure under the confined space of weathered rock geological layer. Background Technology
[0002] In traditional underground engineering construction, deep foundation pit construction requires the prior construction of retaining structures and supporting structures, followed by slope excavation. In deep foundation pit construction adjacent to existing structures, both the safety of the construction process and the impact of excavation on the safety of the existing structures must be considered. In this particular section, the close proximity of the foundation pit to the adjacent existing structure results in insufficient working space for support and slope excavation. Due to the small net spacing between bored piles and other engineering piles, there is insufficient space to construct retaining piles as the foundation pit retaining structure. Therefore, how to construct the foundation pit retaining structure under the condition of limited working space due to the small distance from the adjacent existing structure has become an urgent problem to be solved in this field. Utility Model Content
[0003] The purpose of this invention is to provide a foundation pit retaining structure in a confined space under weathered rock geological layers, so as to solve the problem that it is impossible to construct a foundation pit retaining structure under the condition that the distance to the adjacent existing structure is small and the operating space is limited.
[0004] To address the aforementioned technical problems, this utility model also provides a foundation pit retaining structure for a confined space within a weathered rock geological layer. This structure includes a foundation pit retaining hole constructed downwards through the weathered rock geological layer along the foundation pit edge, Larssen sheet piles inserted into the retaining hole, backfill material distributed on both sides of the Larssen sheet piles within the retaining hole, the backfill material below the foundation pit excavation line being a cement mortar mixed with fibers forming a double-sided embedded end of the Larssen sheet piles, and the backfill material above the foundation pit excavation line being a undisturbed soil forming a double-sided compressed and fixed free end of the Larssen sheet piles, with grouting pipes inserted into the retaining hole to pressurize and grout from the water-facing side to the backwater side of the Larssen sheet piles, forming a horizontal water-stop curtain within the soil layer below the bottom of the retaining hole. The foundation pit retaining hole, backfill material, Larssen sheet piles, and horizontal water-stop curtain form a composite structure of sheet wall and water-stopping mechanism.
[0005] Furthermore, in the foundation pit retaining structure under the confined space of the weathered rock geological layer provided by this utility model, multiple horizontal steel bars are vertically and spaced on each concave surface of the Larssen steel sheet pile.
[0006] Furthermore, in the foundation pit retaining structure under the confined space of the weathered rock geological layer provided by this utility model, the horizontal reinforcing bars on the adjacent concave surfaces of the Larssen sheet piles on both the inner and outer sides are staggered.
[0007] Furthermore, in the foundation pit retaining structure under the confined space of the weathered rock geological layer provided by this utility model, grouting pipes are provided along the height of at least a portion of the concave surfaces on the inner and outer sides of the Larssen steel sheet pile.
[0008] Compared with the prior art, the beneficial effects of this utility model are as follows:
[0009] This utility model provides a foundation pit retaining structure for confined spaces in weathered rock geological layers. The retaining hole is formed through pilot-hole construction. Backfill material is filled into the retaining hole, and Larssen sheet piles are inserted within it. The Larssen sheet piles are double-sidedly embedded using fiber-mixed cement mortar as backfill material below the excavation line to improve their deformation resistance. Above the excavation line, the Larssen sheet piles are double-sidedly compressed and fixed using undisturbed soil as backfill material, preventing displacement or deformation due to disturbance of the undisturbed soil by adjacent pilot-hole sections or collisions. The composite structure formed by the backfill material and the Larssen sheet piles within the retaining hole stably fixes the Larssen sheet piles within the retaining hole, enhancing the stability of the foundation pit retaining structure and ensuring the safety of the foundation pit under stress. This solves the problem of being unable to construct foundation pit retaining structures under conditions of limited operating space due to small distances from adjacent existing structures. The fibers in the cement mortar can solidify together with groundwater, stabilizing Larssen sheet piles. At the same time, the fibers can enhance toughness, improve the strength of the early solidified body, and effectively transfer and disperse stress, thereby reducing the generation and propagation of cracks.
[0010] This utility model provides a foundation pit retaining structure for confined spaces in weathered rock geological layers. By constructing a horizontal water-stop curtain at the bottom of the foundation pit retaining hole, it prevents groundwater from seeping above the excavation line. The backfill material below the excavation line is fiber-mixed cement mortar, which double-sidedly embeds Larssen sheet piles to form vertical water-stop curtains on both sides of the Larssen sheet piles. This solves the problem of groundwater leakage in the retaining system caused by construction, providing excellent conditions for the subsequent construction of the basement structure. The foundation pit retaining structure, which forms a composite structure of retaining hole, backfill material, Larssen sheet piles, and water-stop curtain, improves the load-bearing performance of the foundation pit retaining structure and enhances the three-sided water-stopping effect.
[0011] The foundation pit retaining structure provided by this utility model under the confined space of weathered rock geological layer can solve the problem of deep foundation pit retaining engineering in confined operating space where traditional support and slope excavation are not feasible. It can complete the construction of a high-strength, low-deformation foundation pit retaining structure system in a short time, thereby avoiding the risk of foundation pit collapse due to long-term exposure without retaining structure. Attached Figure Description
[0012] Figure 1This is a schematic diagram of the plan structure of the foundation pit retaining structure under the confined space of the weathered rock geological layer;
[0013] Figure 2 yes Figure 1 Schematic diagram of the cross-sectional structure at point AA;
[0014] Figure 3 yes Figure 1 Schematic diagram of the cross-sectional structure at point BB;
[0015] As shown in the figure:
[0016] 100. Foundation pit retaining structure; 110. Foundation pit retaining hole; 111. Foundation pit excavation bottom line; 120. Backfill material; 121. Free end; 122. Embedded end; 130. Larssen sheet pile; 131. Grouting pipe; 132. Horizontal reinforcement; 140. Horizontal water-stop curtain. Detailed Implementation
[0017] The present invention will now be described in detail with reference to the accompanying drawings. The advantages and features of the present invention will become clearer from the following description. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the present invention.
[0018] Please refer to Figures 1 to 3 This utility model embodiment provides a foundation pit retaining structure 100 in a confined space under weathered rock geological layer, including a foundation pit retaining hole 110 constructed downward through the weathered rock geological layer along the edge of the foundation pit, Larssen steel sheet piles 130 inserted into the foundation pit retaining hole 110, backfill material 120 distributed on both sides of the Larssen steel sheet piles 130 filling the foundation pit retaining hole 110, and the backfill material 120 located below the bottom line of the foundation pit excavation is cement mortar mixed with fibers to form a double-sided embedding end 1 of the Larssen steel sheet piles 130. 22. The backfill material 120 located above the excavation bottom line is formed by the free end 121 of the Larssen sheet pile 130 through double-sided compression and fixation of the original soil. A grouting pipe 131 is inserted into the retaining hole 110 of the excavation pit, and pressurized grouting is performed from the water-facing side to the backwater side of the Larssen sheet pile 130 to form a horizontal water-stopping curtain 140 in the soil layer below the bottom of the retaining hole 110. The retaining hole 110, backfill material 120, Larssen sheet pile 130, and horizontal water-stopping curtain 140 form a composite structure of sheet wall water-stopping. The backfill material 120 ensures the safety of the excavation process in this section and the stability of the existing structures in adjacent sections.
[0019] Please refer to Figure 1The present invention provides a foundation pit retaining structure 100 for confined spaces in weathered rock geological layers, wherein multiple horizontal reinforcing bars 132 are vertically welded at intervals on each concave surface of the Larssen sheet piles 130. To improve the fixing effect with the backfill material, each row of horizontal reinforcing bars 132 on each concave surface can be arranged in two parallel rows. The horizontal reinforcing bars 132 can be welded using waste steel bar ends from the construction site, meeting the "material-saving" requirements of green construction, reducing the disposal of a large amount of scrap steel, and promoting the recycling of resources. Alternatively, the horizontal reinforcing bars 132 can be replaced with studs to improve the fixing effect between the Larssen sheet piles 130 and the backfill material 120. To improve the effect of balanced fixing, the horizontal reinforcing bars 132 on adjacent concave surfaces on the inner and outer sides of the Larssen sheet piles 130 can be staggered.
[0020] Please refer to Figure 1 In order to construct a horizontal water-stop curtain 140 in the soil layer below the bottom of the foundation pit retaining hole 110, the foundation pit retaining structure 100 under the confined space of the weathered rock geological layer provided in this utility model embodiment has grouting pipes 131 arranged along its height on at least part of the concave surface of the inner and outer sides of the Larssen steel sheet pile 130.
[0021] The foundation pit retaining structure 100 provided in this embodiment of the utility model for confined spaces in weathered rock geological layers forms a foundation pit retaining hole 110 through pilot hole construction. Backfill material 120 is filled into the retaining hole 110, and Larssen steel sheet piles 130 are inserted within it. The Larssen steel sheet piles 130 are double-sidedly embedded in the backfill material 120 (which is fiber-mixed cement mortar) below the foundation pit excavation line to improve their deformation resistance. The Larssen steel sheet piles 130 are further reinforced by the backfill material 120 (which is undisturbed soil) above the foundation pit excavation line. The Larssen sheet piles 130 are fixed by double-sided compression to prevent them from shifting or deforming due to disturbance of the original soil by adjacent pilot holes or collisions. The composite structure formed by the backfill material 120 within the retaining hole 110 and the Larssen sheet piles 130 stabilizes the Larssen sheet piles 130 within the retaining hole 110, enhancing the stability of the retaining system and ensuring the safety of the foundation pit under stress. This solves the problem of being unable to construct the retaining structure 100 when the distance to adjacent existing structures is small, resulting in limited operating space. The fibers in the cement mortar can solidify together with groundwater, stabilizing the Larssen sheet piles 130. Simultaneously, the fibers enhance toughness, improve the strength of the early-cured body, and effectively transfer and disperse stress, thereby reducing the generation and propagation of cracks.
[0022] The foundation pit retaining structure 100 provided in this embodiment of the utility model, located in a confined space within a weathered rock geological layer, prevents groundwater from seeping above the excavation line by constructing a horizontal water-stopping curtain 140 at the bottom of the foundation pit retaining hole 110. Vertical water-stopping curtains are formed on both sides of the Larssen sheet piles 130 by using backfill material 120 (cement mortar mixed with fibers) located below the excavation line to double-sidedly embed the Larssen sheet piles 130. This solves the problem of groundwater leakage in the retaining system caused by construction, providing excellent conditions for the subsequent construction of the basement structure. The foundation pit retaining structure 100, formed by the foundation pit retaining hole 110, backfill material 120, Larssen sheet piles 130, and water-stopping curtains, improves the load-bearing performance of the foundation pit retaining structure 100 and enhances its three-sided water-stopping effect.
[0023] The foundation pit retaining structure 100 provided in this embodiment of the utility model can solve the problem of deep foundation pit retaining engineering in which traditional support and slope excavation are not possible in the limited operating space. It can complete the construction of a high-strength, low-deformation foundation pit retaining structure 100 system in a short time, thereby avoiding the risk of foundation pit collapse due to long-term exposure without retaining structure.
[0024] The foundation pit retaining structure 100 provided in this embodiment of the utility model for confined spaces in weathered rock geological layers can solve the difficulties of constructing the foundation pit retaining structure 100 deep into geological layers in complex geological environments, ensuring the smooth construction of underground projects and guaranteeing construction progress and quality. The foundation pit retaining structure 100 in the example shown in the figure is constructed in the following geological layers from top to bottom: miscellaneous fill, hard cohesive soil, completely weathered mixed rock, strongly weathered mixed rock (soil-like), strongly weathered mixed rock (blocky), moderately weathered mixed rock, and slightly weathered mixed rock. However, it is not limited to construction in weathered rock geological layers and can be applied to construction in other hard geological layers.
[0025] This utility model is not limited to the specific embodiments described above. Obviously, the embodiments described above are only some, not all, of the embodiments of this utility model. Based on the described embodiments of this utility model, all other embodiments obtained by those skilled in the art are within the scope of protection of this utility model. Those skilled in the art can make other levels of modifications and variations to this utility model. Therefore, if these modifications and variations of this utility model fall within the scope of the claims of this utility model, this utility model also intends to include these modifications and variations.
Claims
1. A foundation pit retaining structure for a confined space within a weathered rock geological layer, characterized in that, The structure includes a retaining hole for the foundation pit constructed downwards through the weathered rock geological layer along the edge of the foundation pit; Larssen sheet piles inserted into the retaining hole; backfill material distributed on both sides of the Larssen sheet piles and filling the retaining hole; the backfill material below the excavation bottom line is cement mortar mixed with fibers to form the embedded end of the Larssen sheet piles on both sides; the backfill material above the excavation bottom line is undisturbed soil to form the free end of the Larssen sheet piles by squeezing and fixing them on both sides; and a horizontal water-stop curtain is formed in the soil layer below the bottom of the retaining hole by pressurized grouting from the water-facing side to the water-repellent side of the Larssen sheet piles through grouting pipes inserted into the retaining hole. The retaining hole, backfill material, Larssen sheet piles, and horizontal water-stop curtain form a composite structure of sheet wall water-stopping.
2. The foundation pit retaining structure under confined space in weathered rock geological strata according to claim 1, characterized in that, The Larsen sheet piles have multiple horizontal reinforcing bars welded vertically at intervals on each concave surface.
3. The foundation pit retaining structure under confined space in weathered rock geological layer according to claim 2, characterized in that, The horizontal reinforcing bars on the adjacent concave surfaces of the inner and outer sides of the Larsen sheet pile are staggered.
4. The foundation pit retaining structure under confined space in weathered rock geological strata according to claim 1, characterized in that, At least a portion of the concave surfaces on the inner and outer sides of the Larssen sheet pile are provided with grouting pipes along their height.