Construction method of soil-rock combined stratum caisson structure

Abstract

The present application relates to a kind of soil and rock combined stratum caisson structure construction method, install first cylinder, install profiled steel baffle, install second section cylinder, according to the N section cylinder, bottom plate concave layer excavation, cushion, reinforced concrete construction, the profiled steel baffle of the present application is cleaned after removal, can be recycled to other similar projects.Profiled steel baffle length direction has certain flexibility, can be curved to a certain extent, so that multiple profiled steel baffle is assembled to different diameter circumference, satisfy the caisson construction of different size.

Description

Technical Field

[0001] This invention relates to civil engineering, specifically to a construction method for a caisson structure in soil-rock combined strata. Background Technology

[0002] like Figure 2 As shown: In civil engineering, the traditional construction method for caissons involves constructing a section of the caisson cylinder on the ground, then excavating and sinking the bottom of the cylinder, and then continuing construction of the upper cylinder, repeating this process until the design elevation is reached. In the structural design, horizontal reinforcing bars or grooves are left above the bottom cutting edge to facilitate connection with the base slab, increasing structural strength and enhancing waterproofing. However, this method and construction have several problems: 1. The caisson structure has many horizontal joints, which is detrimental to waterproofing and structural load-bearing capacity. 2. Because excavation and sinking are required near the cutting edge on the inner side of the cylinder, the grooves or reserved reinforcing bars of the base slab must maintain a certain distance (generally 2-3 meters) from the cutting edge to facilitate excavation operations and provide sufficient space for each sinking. This means the reserved position of the base slab will be located above the cutting edge. 3. The side walls of the caisson cylinder are generally buried deeper than the base slab, serving as a retaining structure to prevent soil from the outside from squeezing into the cylinder. Furthermore, the excavated portion below the base slab requires backfilling with low-grade concrete for weight-bearing measures. These methods are suitable for soft sandy soil areas where the foundation pit soil is relatively weak. However, this traditional technique will not be applicable when the soil and rock are combined. The geology contains rock layers and the structure is relatively stable, so the caisson body does not need to be excavated to a depth greater than the bottom slab. Summary of the Invention

[0003] This invention aims to overcome the shortcomings of existing technologies and provide a construction method for caisson structures in soil-rock combined strata. It solves the problems of traditional processes in soil-rock combined geological conditions where the upper part is soft soil and the lower part is rock, where caissons are difficult to excavate when encountering hard soil layers (rock, etc.), have many joints, and have slow construction progress.

[0004] To solve the above-mentioned technical problems, the present invention is implemented as follows:

[0005] A construction method for a caisson structure in soil-rock combined strata, characterized by comprising the following steps:

[0006] Step 1: Measure and lay out the lines to determine the location and dimensions of the caisson;

[0007] Step 2: Based on the template support operation process, mark out the working surface dimensions along the outer perimeter of the caisson;

[0008] Step 3: Excavate the caisson foundation pit along the radius of the working surface and according to the geological and soil conditions. Excavate on a slope until you reach a layer that is difficult to excavate with traditional machinery, a relatively hard soil layer, or a rock layer. The depth should be controlled to be less than 5 meters.

[0009] Step 4: Construct the first section of the caisson structure within the foundation pit, with a cutting edge at its lower end;

[0010] Step 5: Leave a tongue-and-groove joint in the upper part of the cutting edge, sloping towards the bottom of the pit;

[0011] Step Six: After the cutting edge is demolded, use the matching prefabricated steel baffle to embed into the tongue and groove to fill the cutting edge;

[0012] Step 7: Excavate the soil inside the caisson, sink the caisson to the predetermined elevation, construct the upper structure of the caisson, and repeat the construction until the cutting edge of the caisson reaches the designed bearing layer.

[0013] Step 8: After excavating to the design elevation, remove the steel baffle at the groove, clean the groove, and chisel away the concrete protective layer inside the groove to expose the reinforcing steel.

[0014] Step 9: Continue digging downwards, using a basin-like method, digging in the middle and not digging around the cutting edge to ensure that the cutting edge has sufficient foundation support.

[0015] Step 10: After the excavation has provided a sufficient working surface, weld the diagonal tie bars of the bottom plate into the groove, and then carry out the construction of the slope cushion layer, reinforcement, and formwork.

[0016] Step 11: Backfill and compact the top and surrounding area of ​​the caisson;

[0017] Step 12: Continue excavating the middle of the caisson, sloping the excavation from the cutting edge towards the center of the caisson, so that the excavation depth of the bottom slab is greater than the depth of the surrounding caisson cylinder, forming a concave shape, until the bottom slab reaches the design elevation, and then carry out the construction of the subbase, reinforcement, concrete, etc., until the overall construction of the caisson is completed.

[0018] The construction method of the soil-rock combined caisson structure is characterized in that: the height of the first section of the caisson structure does not exceed 9 meters.

[0019] The construction method of the soil-rock combined caisson structure is characterized in that: the depth of the tongue and groove is 100-300mm.

[0020] The construction method of the soil-rock combined caisson structure is characterized in that: the steel baffle is made of long steel plates (panels) with short stiffening ribs welded together; the width and thickness of the steel plates match the pre-reserved groove at the caisson, and the steel baffle is provided with bolt holes and is connected to the caisson groove with bolts.

[0021] The beneficial effects of the present invention are as follows: As can be seen from the above technical solution, this application provides a construction method for a caisson structure in a soil-rock combined stratum, which includes installing the first cylinder, installing the steel baffle, installing the second cylinder, installing the Nth cylinder, excavating the concave layer under the bottom plate, constructing the cushion layer, and constructing reinforced concrete.

[0022] After removal and cleaning, the steel baffles can be reused in other similar projects. The steel baffles possess a certain degree of flexibility along their length, allowing for bending and assembly of multiple baffles to create different diameters and circumferences, accommodating caisson construction of varying sizes. This application reduces the amount of excavation, especially in hard rock formations, minimizing blasting and crushing processes, thus accelerating construction progress; it also reduces horizontal construction joints in the caisson structure, enhancing overall structural rigidity and waterproofing performance. Compared to traditional methods, the bottom of the caisson does not require extensive concrete filling, reducing material input and saving costs. Attached Figure Description

[0023] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments:

[0024] Figure 1 This is a schematic diagram of the caisson structure in this application.

[0025] Figure 2 This is a schematic diagram of a traditional caisson structure.

[0026] Figure 3 This is a schematic diagram of the construction of the first cylinder.

[0027] Figure 4 This is a schematic diagram of the installation of the steel baffle.

[0028] Figure 5 This is a schematic diagram of the construction of the second section of the cylinder.

[0029] Figure 6 This is a schematic diagram of the construction of the Nth section of the cylinder.

[0030] Figure 7 Schematic diagram of the excavation, subbase, and reinforced concrete construction of the recessed layer under the base slab. Figure 1 .

[0031] Figure 8 Schematic diagram of the excavation, subbase, and reinforced concrete construction of the recessed layer under the base slab. Figure 2 . Detailed Implementation

[0032] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection claimed in this application.

[0033] like Figure 3-8 As shown: A construction method for a caisson structure in soil-rock combined strata includes the following steps:

[0034] 1. Measure and mark out the location and dimensions of the caisson; 2. Based on the formwork support construction process, mark out the working surface dimensions along the perimeter of the caisson; 3. Excavate the caisson foundation pit along the radius of the working surface dimensions, according to the geological and soil conditions, with sloping excavation, excavating to layers that are difficult to excavate with traditional machinery, such as hard soil or rock layers, with a depth controlled below 5 meters; 4. Construct the first section of the caisson structure (including the cutting edge) within the foundation pit; 5. Depending on the scaffolding and formwork construction capabilities, the height of the first section of the caisson can be as high as possible. However, it generally does not exceed 9 meters; 6. Among them, a tongue and groove inclined towards the bottom of the pit is left in the upper part of the cutting edge, and the depth of the tongue and groove groove is 100-300mm; 7. After the cutting edge is demolded, a matching precast steel baffle is embedded in the tongue and groove groove to fill the cutting edge; 8. Excavation of the soil in the caisson, sinking the caisson to the predetermined elevation, construction of the upper structure of the caisson, and cyclic construction until the cutting edge of the caisson reaches the design bearing layer; 9. The steel baffle is made of long steel plates (panels) with short stiffening ribs welded together. The width and thickness of the steel plates match the groove reserved at the caisson. The steel baffle is provided with bolt holes and is connected to the caisson groove with bolts. The number of bolts and the length of the baffle are limited to what two workers can typically handle for installation and removal; 10. The purpose of this steel baffle is to seal the groove at the cutting edge, maintain the integrity of the cutting edge's slope, prevent soil and rock from getting stuck in the groove and affecting the caisson's sinking, and ensure a smooth transition; 11. After excavating to the design elevation, remove the steel baffle at the groove, clean the groove, and chisel away the concrete protective layer inside the groove to expose the reinforcing steel; 12. Continue excavating downwards, using a basin-style excavation method, excavating in the middle (using blasting or rock drills, etc.), and not excavating around the cutting edge. 13. After excavation has provided sufficient working surface, weld the diagonal reinforcing bars of the bottom plate in the groove, and carry out the construction of the slope cushion layer, reinforcing bars, and formwork; 14. At the same time, backfill and compact the top of the caisson; 15. Continue to excavate the middle of the caisson, sloping the excavation from the cutting edge towards the center of the caisson, so that the excavation depth of the bottom plate is greater than the depth of the surrounding caisson cylinder, forming a concave shape, until the bottom plate reaches the design elevation, and carry out the construction of the cushion layer, reinforcing bars, concrete, and other related works until the overall construction of the caisson is completed.

[0035] After the steel baffles in this application are removed and cleaned, they can be reused in other similar projects. The steel baffles have a certain degree of flexibility along their length, allowing them to be bent to allow multiple steel baffles to be assembled into different diameters and circumferences, meeting the needs of caisson construction of different sizes.

[0036] The above are merely embodiments provided in this application and are not intended to limit this application. Although this application has been described in detail with reference to the embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. However, any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A construction method for a caisson structure in soil-rock combined strata, characterized in that... It includes the following steps: Step 1: Measure and lay out the lines to determine the location and dimensions of the caisson; Step 2: Based on the template support operation process, mark out the working surface dimensions along the outer perimeter of the caisson; Step 3: Excavate the caisson foundation pit along the radius of the working surface and according to the geological and soil conditions, excavating to a layer that is difficult to excavate with traditional machinery, a relatively hard soil layer or a rock layer, with the depth controlled below 5m; Step 4: Construct the first section of the caisson structure within the foundation pit, with a cutting edge at its lower end; Step 5: Leave a tongue and groove that slopes towards the bottom of the pit in the upper part of the cutting edge, with a groove depth of 100-300mm; Step Six: After the cutting edge is demolded, use the matching prefabricated steel baffle to embed into the tongue and groove to fill the cutting edge; Step 7: Excavate the soil inside the caisson, sink the caisson to the predetermined elevation, construct the upper structure of the caisson, and repeat the construction until the cutting edge of the caisson reaches the designed bearing layer. Step 8: After excavating to the design elevation, remove the steel baffle at the groove, clean the groove, and chisel away the concrete protective layer inside the groove to expose the reinforcing steel. Step 9: Continue digging downwards, using a basin-like method, digging in the middle and not digging around the cutting edge to ensure that the cutting edge has sufficient foundation support. Step 10: After the excavation has provided a sufficient working surface, weld the diagonal tie bars of the bottom plate into the groove, and then carry out the construction of the slope cushion layer, reinforcement, and formwork. Step 11: Backfill and compact the top and surrounding area of ​​the caisson; Step 12: Continue excavating the middle part of the caisson, sloping the excavation from the cutting edge towards the center of the caisson, so that the excavation depth of the bottom slab is greater than the depth of the surrounding caisson cylinder, forming a concave shape, until the bottom slab reaches the design elevation, and then carry out the construction of the cushion layer, reinforcement, and concrete until the overall construction of the caisson is completed. The height of the first section of the caisson structure does not exceed 9 meters; The steel baffle is made of long steel plates with short stiffening ribs welded together; the width and thickness of the steel plates match the pre-reserved groove at the caisson, and the steel baffle is provided with bolt holes, which are used to connect it to the caisson groove with bolts.

Images