Excavation method for open cut foundation pit of subway station
By using the excavation method of small-mile and large-mile ends in the subway station foundation pit, and excavating T-pits and horse lanes at the large-mile end to allow equipment to pass, the problem of difficult equipment entering when the subway station foundation pit is opened is solved, and the construction safety, cost-effectiveness and high efficiency are achieved.
Patent Information
- Application Number
- CN202510071467.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-16
- Publication Date
- 2025-04-15
AI Technical Summary
When the foundation pit of the subway station is excavated, it is difficult for excavators and other equipment to enter the foundation pit, which is costly and difficult.
The excavation method is adopted in which each section of the foundation pit includes a small mileage end and a large mileage end. By excavating to the bottom of the concrete brace at the small mileage end and setting up a concrete support, the first T-shaped pit with a depth of D1 is excavated at the large mileage end, and excavating along the length of the foundation pit to form a horse path to allow the excavation equipment to pass. Then, a 10-20° slope excavation is used to excavate and excavate as a whole, layered excavation is carried out and steel supports are erected and prestressed is applied.
The excavation equipment can enter the foundation pit through the horse path for subsequent digging operations, and the entire construction process is safe, low in cost and high in efficiency.
Smart Images
Figure CN119824921A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of subway station excavation, and in particular to an excavation method for an open excavation pit of a subway station. Background Art
[0002] With the continuous development of urban construction in my country, the surrounding environment of urban subways is becoming more and more complex, and subway construction is restricted by more and more factors. Open-cut method and dark-cut method are two commonly used construction methods for subway stations. Open-cut method has the advantages of fast construction speed, high safety, low cost and short construction period. Dark-cut method has the problems of high comprehensive cost, great construction difficulty, poor safety and long construction period.
[0003] However, it is difficult for excavators and other equipment to enter the foundation pit to carry out operations during the open excavation of subway station foundation pits, resulting in high cost and difficulty in the open excavation of subway station foundation pits. Summary of the invention
[0004] In order to solve the above technical problems or at least partially solve the above technical problems, the present disclosure provides a method for excavating an open excavation pit of a subway station.
[0005] The present disclosure provides an excavation method for an open excavation foundation pit of a subway station, comprising:
[0006] S1, each section of the foundation pit includes a small mileage end and a large mileage end. At the small mileage end, excavation is carried out to the bottom of the concrete support, and concrete support is erected;
[0007] S2, excavate the first T-shaped pit with a depth of D1 at the large mileage end;
[0008] S3, on the basis of the first T-shaped pit, excavate along the length direction of the foundation pit toward the small mileage end to form a horse path, the horse path can allow the excavation equipment to pass, and set up a first steel support;
[0009] S4, adopt 10-20° slope trench excavation, push excavation from the small mileage end to the large mileage end as a whole, excavate in layers during the excavation process, set up the second steel support and apply prestress.
[0010] Optionally, S5, after the second steel support is installed, remove the slope protection soil below, push the whole steel support flat and excavate in layers, set up the third steel support and apply prestress, and excavate to 0.8m-1m below the third steel support before removing the slope protection soil below.
[0011] Optionally, S6, continue to excavate downward to the base, continue to push the excavation along the slope of 10-20° from the small mileage end to the large mileage end, remove the slope protection soil on both sides, and when excavating to the large mileage end, enter the second stage where the excavator relays to close the slope and discharge the slag.
[0012] Optionally, S7 uses excavators to push down layer by layer in relays.
[0013] Optional, S8, when excavation reaches the end of the large mileage, it is impossible to relay excavation. Use an excavator in conjunction with vertical lifting excavation. The excavated earth is vertically lifted and transported by a long-arm excavator or crane to excavate the large mileage to the bottom.
[0014] Optionally, in step S2, D1 is 6.5 mm, and a construction platform for the first steel support is reserved on both sides of the first T-shaped pit.
[0015] Optionally, in step S3, the first steel support is erected when the excavation depth of the soil shoulders on both sides of the first steel support reaches 0.9 m below the first steel support.
[0016] Optionally, in step S2, the first T-shaped pit is excavated in layers, and the layer height should fully consider the geological conditions of the excavation pit, and the thickness of each excavation layer should be determined in combination with the water content and stability of the surrounding rock. Under the premise of meeting safety requirements, the thickness of each excavation layer shall not exceed 3m.
[0017] Optionally, the foundation pit is divided into multiple construction sections, each construction section is 19m in length.
[0018] Optionally, the foundation pit is excavated with a slope of 10-20° as a whole, and the concrete support part at the long mileage end of the station body is backfilled as a slag discharge ramp, and at least part of the ramp has a slope of 20°-25°.
[0019] Compared with the prior art, the technical solution provided by the embodiments of the present disclosure has the following advantages:
[0020] The excavation method of the open-cut foundation pit of a subway station provided by the embodiment of the present disclosure includes S1, each section of the foundation pit includes a small mileage end and a large mileage end, excavating to the bottom of the concrete support at the small mileage end, and setting up the concrete support; S2, excavating a first T-shaped pit with a depth of D1 at the large mileage end; S3, excavating along the length direction of the foundation pit toward the small mileage end on the basis of the first T-shaped pit to form a horseway, the horseway can allow the excavation equipment to pass, and setting up the first steel support; S4, adopting a 10-20° slope groove excavation, pushing the excavation from the small mileage end to the large mileage end as a whole, excavating in layers during the excavation process, setting up the second steel support and applying prestress. The excavation equipment can enter the foundation pit from the horseway to carry out subsequent pit excavation operations, and the entire construction process is safe, low-cost and high-efficiency. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.
[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.
[0023] Figure 1 The structure diagram of the excavation method of the open excavation pit of the subway station according to the embodiment of the present disclosure is shown in FIG. Figure 1 ;
[0024] Figure 2 The structure diagram of the excavation method of the open excavation pit of the subway station according to the embodiment of the present disclosure is shown in FIG. Figure 2 ;
[0025] Figure 3 The structure diagram of the excavation method of the open excavation pit of the subway station according to the embodiment of the present disclosure is shown in FIG. Figure 3 ;
[0026] Figure 4 The structure diagram of the excavation method of the open excavation pit of the subway station according to the embodiment of the present disclosure is shown in FIG. Figure 4 ;
[0027] Figure 5 The structure diagram of the excavation method of the open excavation pit of the subway station according to the embodiment of the present disclosure is shown in FIG. Figure 5 ;
[0028] Figure 6 The structure diagram of the excavation method of the open excavation pit of the subway station according to the embodiment of the present disclosure is shown in FIG. Figure 6 ;
[0029] Figure 7 The structure diagram of the excavation method of the open excavation pit of the subway station according to the embodiment of the present disclosure is shown in FIG. Figure 7 ;
[0030] Figure 8 The structure diagram of the excavation method of the open excavation pit of the subway station according to the embodiment of the present disclosure is shown in FIG. Figure 8 ;
[0031] Fig. 9 The structure diagram of the excavation method of the open excavation pit of the subway station according to the embodiment of the present disclosure is shown in FIG. Figure 9 ;
[0032] Fig.10 It is a general drawing of temporary support for downward-flipped beams, wastewater pools, sunken structures, etc.
[0033] Among them, X is the short mileage end; D is the long mileage end. DETAILED DESCRIPTION
[0034] In order to more clearly understand the above-mentioned objectives, features and advantages of the present disclosure, the scheme of the present disclosure will be further described below. It should be noted that the embodiments of the present disclosure and the features in the embodiments can be combined with each other without conflict.
[0035] In the following description, many specific details are set forth to facilitate a full understanding of the present disclosure, but the present disclosure may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present disclosure, rather than all of the embodiments.
[0036] With the continuous development of urban construction in my country, the environment around urban subways is becoming more and more complex, and subway construction is restricted by more and more factors. Open-cut method and dark-cut method are two commonly used construction methods for subway stations. Open-cut method has the advantages of fast construction speed, high safety, low cost and short construction period. Dark-cut method has the problems of high comprehensive cost, high construction difficulty, poor safety and long construction period. However, when excavating the foundation pit of subway stations, it is difficult for excavators and other equipment to enter the foundation pit to carry out operations, resulting in high cost and difficulty in the open-cut method of subway station foundation pits.
[0037] Based on this, refer to Figures 1 to 10 As shown in the figure (the arrow direction in the figure is the excavation direction), this embodiment provides an excavation method for an open excavation foundation pit of a subway station, including: S1, each section of the foundation pit includes a small mileage end X and a large mileage end D, excavating from the small mileage end X to the bottom of the concrete support, and erecting the concrete support. That is, Figure 1 As shown, after the underground continuous wall X at the small mileage end reaches the designed strength, the hardened concrete ground is broken, and excavation is carried out to the position 0.5m-0.8m below the bottom of the first concrete support to provide a working surface for breaking the pile head. Manual and mechanical chiseling are used to remove the excess concrete of the underground continuous wall, and the cap beam, retaining wall and concrete support are constructed.
[0038] S2, dig the first T-shaped pit with a depth of D1 at the long mileage end D. That is to say, Figure 2 As shown in the figure, after the concrete support and crown beam reach the designed strength, the deep foundation pit excavation key node inspection is carried out. After the inspection is completed, the second step of excavation can be carried out. Figure 3 As shown, on the basis of the first T-shaped pit, excavation is carried out along the length direction of the foundation pit toward the small mileage end X to form a horseway, which can allow the excavation equipment to pass through, and the first steel support is set up. Figure 2 and Figure 3As shown, the second step of earthwork excavation starts from the large mileage end D of the station. To ensure that the excavator has enough turnover space, the first layer of excavation depth D1 is 6.5m. 1 to 2 wide slope protection soil is reserved on both sides of the first T-shaped pit (reserved steel support construction platform), the slope gradient is 1:0.75 to 1:1, and the trench is excavated to the small mileage end X. The first steel support at the horseway is set up when the excavation depth of the earth shoulders on both sides of the horseway reaches 0.9m below the center line of the first steel support.
[0039] S4, such as Figure 4 As shown in the figure, the excavation is carried out by cutting the groove with a slope of 10-20°, and the excavation is carried out from the small mileage end X to the large mileage end D as a whole. During the excavation process, the excavation is carried out in layers, and the second steel support is set up and prestressed. That is to say, after the horseway is dug through, the excavation is carried out by cutting the groove with a slope of 10-20°, and the excavation is carried out from the small mileage end X of the station to the large mileage end D as a whole. The excavation is carried out in layers to 0.9m below the center line of the second steel support, the second steel support is set up and prestressed in time, and the slope protection soil under the steel support can be excavated after completion.
[0040] The present embodiment provides a method for excavating an open-cut foundation pit for a subway station. The excavation equipment can enter the foundation pit from the horseway to carry out subsequent excavation operations. The entire construction process is safe, low-cost and highly efficient.
[0041] In some embodiments, S5, after the second steel support is installed, the slope protection soil below is excavated, the whole steel support is pushed flat and excavated in layers, the third steel support is erected and prestressed, and the slope protection soil below is excavated after excavating to 0.8m-1m below the third steel support. Figure 5 and Figure 6 As shown, after the second steel support is installed, the slope protection soil below is excavated, and the overall horizontal excavation is carried out in layers to 0.9m below the center line of the third steel support. The third steel support is erected and prestress is applied in time. After completion, the slope protection soil below the steel support can be excavated.
[0042] In some embodiments, S6, such as Figure 7 As shown, after the third steel support is installed, continue to excavate downward to the base, and continue to push the excavation along the 10-20° slope from the small mileage end X to the large mileage end D, remove the slope protection soil on both sides, and when excavating to the large mileage end D, enter the second stage where the excavator relays to close the slope and discharge the slag.
[0043] In some embodiments, Figure 8 As shown, S7, excavators are used in relays to push the excavation downward layer by layer.
[0044] In some embodiments, S8, such as Fig. 9 As shown, when excavation reaches the end of the large mileage end D, it is impossible to relay excavation. An excavator is used in conjunction with vertical lifting excavation. The excavated earth is vertically lifted and transported by a long-arm excavator or a crane to excavate the large mileage to the bottom.
[0045] S9, after excavating to the bottom of the foundation pit, if there is a base sinking position, first excavate the base sinking part. See the excavation diagram for details. Fig.10 Temporary support drawings for lowered beams, wastewater pools, and sunken structures. The remaining 0.2 to 0.3 m is cleared manually with a small excavator, and the foundation pit is leveled by manual digging and slope repair. After digging to the designed pit bottom elevation, the base inspection trench is carried out in sequence, the concrete cushion layer is poured, and the waterproof layer is applied. The structural bottom plate steel bars are tied and the structural bottom plate is poured. The ladder cage is installed simultaneously as a passage for personnel to go up and down. The ladder cage adopts a heavy-duty safety frame construction ladder cage, which is dismantled and assembled as the progress of the first section of construction.
[0046] In some embodiments, in step S2, D1 is 6.5 mm, and a construction platform for the first steel support is reserved on both sides of the first T-shaped pit.
[0047] In some embodiments, in step S3, the first steel support is erected when the excavation depth of the soil shoulders on both sides of the first steel support reaches 0.9 m below the first steel support.
[0048] In some embodiments, in step S2, the first T-shaped pit is excavated in layers, and the layer height should fully consider the geological conditions of the excavation pit, and the thickness of each excavation layer should be determined in combination with the water content and stability of the surrounding rock. Under the premise of meeting safety requirements, the thickness of each excavation layer shall not exceed 3m.
[0049] In some embodiments, the foundation pit is divided into multiple construction sections, each of which is 19 meters long. The foundation pit is excavated longitudinally in sections according to the station structure and the locations of the steel supports and concrete supports. It is planned to be divided into 10 flow sections, and the foundation pit excavation construction is carried out in sections of 19 meters each. The longitudinal segmentation takes into account that the length of each excavation must meet the requirements of the excavation layer to form a parallel operation of support installation and earthwork excavation, reducing the intermediate pause time. At the same time, there is a certain safety distance between the installation area and the excavation area to avoid safety hazards caused by cross-operation, while taking into account the division of the main construction sections, which is consistent with the setting of the main construction joints, and performs flow operations.
[0050] Mechanical excavation is used on site, and a breaker hammer is required if rock is encountered. When excavating to the steel support position, the length of each unit should be 6-8m (three to four supports). Because the rock layer is broken slowly and considering the working space of the excavator, the steel support within the unit length will be installed after the rock below is broken. The overall excavation and installation time shall not exceed 24 hours (the excavation is completed on the same day and the installation is completed on the same day). The steel support to be installed needs to be assembled on the ground in advance, and the installation shall be carried out when the installation conditions are met, and emergency preparations shall be made at the same time. If the monitoring data within the unit length is abnormal, be sure to stop excavation and set up the steel support in time.
[0051] In some embodiments, the foundation pit is excavated with a slope of 10-20° as a whole. To ensure convenient slag discharge at the long-mileage end, the concrete support part of the long-mileage end of the station body is backfilled as a slag discharge ramp. Considering that the vehicle driving height does not collide with the steel support, at least part of the ramp has a slope of 20°-25°.
[0052] If the remaining soil at the end of the foundation pit cannot be excavated by step-by-step relay excavation, vertical excavation construction is carried out by using a long-arm excavator on the upper part of the foundation pit in conjunction with a base excavator, or an excavator at the bottom of the foundation pit in conjunction with a large crane on the upper part of the foundation pit for vertical transportation.
[0053] Since earthwork is one of the main sub-projects of station construction, in addition to rationally organizing and coordinating construction, excavators with high working efficiency should be selected as much as possible. Based on the previous experience of subway station construction, the method of digging along the slope is adopted. Since the station uses steel supports as the internal support system, the time and space relationship between machinery and supports is reasonably arranged to achieve the purpose of excavators walking along the slope and earthmoving vehicles walking along the slope in the pit to transport the excavated earth.
[0054] It should be noted that, in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.
[0055] The above description is only a specific embodiment of the present disclosure, so that those skilled in the art can understand or implement the present disclosure. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure will not be limited to the embodiments described herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A method for excavating an open excavation pit for a subway station, characterized in that: include: S1, each section of the foundation pit includes a small mileage end and a large mileage end. At the small mileage end, excavation is carried out to the bottom of the concrete support, and concrete support is erected; S2, excavate the first T-shaped pit with a depth of D1 at the large mileage end; S3, on the basis of the first T-shaped pit, excavate along the length direction of the foundation pit toward the small mileage end to form a horse path, the horse path can allow the excavation equipment to pass, and set up a first steel support; S4, adopt 10-20° slope trench excavation, push excavation from the small mileage end to the large mileage end as a whole, excavate in layers during the excavation process, set up the second steel support and apply prestress.
2. The method for excavating an open excavation pit for a subway station according to claim 1, characterized in that: S5, after the second steel support is installed, remove the slope protection soil below, push the whole steel support flat and excavate in layers, set up the third steel support and apply prestress, and excavate to 0.8m-1m below the third steel support before removing the slope protection soil below.
3. The method for excavating an open excavation pit for a subway station according to claim 2, characterized in that: S6, continue to excavate downward to the base, continue to push and excavate along the slope of 10-20° from the small mileage end to the large mileage end, remove the slope protection soil on both sides, and when excavating to the large mileage end, enter the second stage where the excavator relays to close the slope and discharge slag.
4. The method for excavating an open excavation pit for a subway station according to claim 3, characterized in that: S7, use the excavators in relays to push the excavation downwards layer by layer.
5. The method for excavating an open excavation pit for a subway station according to claim 4, characterized in that: S8, when excavation reaches the end of the large mileage, it is impossible to relay excavation. An excavator is used in conjunction with vertical lifting excavation. The excavated earth is lifted vertically and transported out by a long-arm excavator or a crane to excavate the large mileage to the bottom.
6. The method for excavating an open excavation pit for a subway station according to claim 1, characterized in that: In step S2, D1 is 6.5 mm, and a construction platform for the first steel support is reserved on both sides of the first T-shaped pit.
7. The method for excavating an open excavation pit for a subway station according to claim 1, characterized in that: In step S3, the first steel support is erected when the soil shoulders on both sides of the first steel support are excavated to a depth of 0.9 m below the first steel support.
8. The method for excavating an open excavation pit for a subway station according to claim 1, characterized in that: In step S2, the first T-shaped pit is excavated in layers, and the layer height should fully consider the geological conditions of the excavation pit, and combine the water content and stability of the surrounding rock to determine the thickness of each excavation layer. Under the premise of meeting safety requirements, the thickness of each excavation layer shall not exceed 3m.
9. The method for excavating an open excavation pit for a subway station according to claim 1, characterized in that: The foundation pit is divided into multiple construction sections, each of which is 19m long.
10. The method for excavating an open excavation pit for a subway station according to claim 1, characterized in that: The foundation pit is excavated with a slope of 10-20° as a whole, and the concrete support part at the long mileage end of the station body is backfilled as a slag discharge ramp, and at least part of the ramp has a slope of 20°-25°.