A shallow-buried large-section station roof picking construction technology

Abstract

The application discloses a shallow-buried large-section station roof-pulling construction process, which comprises the following steps: step S1, a station front construction passage is located at the left side of a station main body, and the two form a station main body intersection; step S2, the station front construction passage is excavated; step S3, after excavation until reaching the station main body vertical center line, the excavation slope is adjusted to be flat, and the excavation is continued to the right end of the station main body; step S4, after the upper section construction reaches a preset distance L1, the lower section excavation is started; the upper section excavation and the lower section excavation are kept synchronous, and the two always keep the preset distance L1, until the lower section excavation is completed, and then the support between the upper section and the lower section is removed. The construction method divides the whole station roof-pulling into sections, and each section is excavated in blocks, so that the excavation stability is high, the collapse in the excavation process is not prone to occur, the construction speed is relatively high, and the construction period is greatly shortened.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of roof picking construction of shallow-buried large-section excavated station. More particularly, the present application relates to a roof picking construction process of shallow-buried large-section excavated station. BACKGROUND

[0002] The significant features of urban subway engineering are shallow burying, poor geological conditions, dense surface buildings and underground pipelines. These features determine that subway construction will have a great impact on the surrounding environment. When the large-section shallow-buried subway station is constructed by the excavation method, due to the large excavation section of the station main body, multiple operation faces and complex construction procedures, the construction period is tight, which will have a great impact on the safety of the surrounding environment.

[0003] With the rapid progress of tunnel construction technology and design theory, the span and section area of large-section tunnels in China will develop towards a larger trend in future construction. With the increasing tunnel mileage year by year, different forms of sections and different degrees of geological conditions will be encountered in the construction process. At the same time, the construction of shallow-buried excavated station itself is an engineering problem. At present, there is little research on the construction technology of shallow-buried large-section excavated station at home and abroad. The conventional method cannot be completely applied to the construction of shallow-buried large-section excavated station because of the risk of large deformation and collapse, which has great safety hazards, and the construction cost is high and the construction period is long. SUMMARY

[0004] In order to achieve these objects and other advantages of the present application, a roof picking construction process of shallow-buried large-section excavated station is provided, comprising the following steps:

[0005] Step S1, according to the site conditions and construction criteria, design construction drawings, wherein the cross section of the station front construction passage is square, the cross section of the station main body is semicircular, the station front construction passage is located on the left side of the station main body, and the two intersect to form a station main body intersection;

[0006] Step S2, excavate the station front construction passage, and excavate the station main body at the station front construction passage bottom according to the slope of 22%, in the process, the excavation forms a section at the station main body intersection;

[0007] Step S3, after excavation until reaching the vertical center line of the station main body, adjust the excavation slope to flat, continue to excavate to the right end of the station main body, and divide the station main body into upper and lower sections along the slope line,

[0008] wherein during the excavation process of the upper section, a supporting steel truss is arranged at the excavated position every 3 meters, and a steel structure is arranged on the top surface, side surface and ground surface of the excavated position respectively, and concrete is sprayed on the surface to support the excavation section;

[0009] Step S4, when the upper section is constructed to the preset distance L1, the lower section is excavated, and during the excavation of the lower section, every 2 meters of the upper section is excavated, the corresponding supporting steel truss at the excavated position is lengthened, and steel structures are respectively arranged on both sides of the excavated position, and concrete is sprayed on the surface thereof to support the excavated section;

[0010] The upper section excavation and the lower section excavation are kept synchronous, and the distance between them is always kept at the preset distance L1,

[0011] until the excavation of the lower section is completed, and then the support between the upper section and the lower section is removed.

[0012] Preferably, in step S1, before construction, the excavation contour line is lofted, and non-explosive excavation is performed by using a cantilever excavator,

[0013] Preferably, during construction, the ground surface settlement of the tunnel peripheral soil, the vault settlement of the tunnel structure vault, the clearance convergence of the tunnel structure haunch, the structure stress at the end surface conversion position, and the stress concentration position are monitored and measured.

[0014] Preferably, during the excavation of the upper section / lower section, the to-be-excavated section of the upper section / lower section is divided into a left side chamber and a right side chamber;

[0015] The left side chamber is excavated first, and during the excavation of the left side chamber, every 4 meters, a supporting steel truss is arranged at the excavated position, and steel structures are respectively arranged on the top surface, the side surface, and the ground surface of the excavated position, and concrete is sprayed on the surface thereof;

[0016] When the left side chamber is excavated to the preset length L2, the right side chamber is excavated, and during the excavation of the right side chamber, every 4 meters, a supporting steel truss is arranged at the excavated position, and steel structures are respectively arranged on the top surface, the side surface, and the ground surface of the excavated position, and concrete is sprayed on the surface thereof;

[0017] The excavation of the left side chamber and the right side chamber is kept synchronous, and the distance between them is always kept at the preset distance L2, until the excavation of the lower section is completed, and then the support between the left side chamber and the right side chamber is removed.

[0018] Preferably, in step S4, the bottom of the supporting steel truss after lengthening treatment is supported on a hard platform, and the strength of the hard platform exceeds the preset strength.

[0019] Preferably, according to the shallow-buried large-section underground station roof construction process of claim 3, characterized in that, in step S4, the monitoring and measurement process is completed on the monitoring points on the monitoring section, the monitoring section is arranged 5 meters in front of the excavated section, the monitoring section is perpendicular to the center line of the excavation line, and the monitoring points are multiple.

[0020] Preferably, in the step S2, the section is changed from a portal section to an arch section at the station main intersection, and the process adopts a rock drill combined with a boom jumbo to perform the excavation operation.

[0021] Preferably, in the step S4, the steel truss at the station main intersection needs to be reinforced during the excavation of the section.

[0022] The construction method of the present application has the following beneficial effects: the construction method of the present application divides the whole station roof into segments for construction, and each segment is excavated in blocks, so that the excavation stability is high, and the collapse during excavation is less likely to occur, and the construction speed is faster, and the construction period is greatly shortened.

[0023] Other advantages, objects, and features of the present application will be apparent to those skilled in the art from the following description, and will be understood to be within the scope of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 The figure is a schematic diagram of the construction layout of the shallow-buried large-section underground station roof construction in the present application. DETAILED DESCRIPTION

[0025] The present application will be further described in detail below with reference to the accompanying drawings, so that those skilled in the art can implement the present application according to the description.

[0026] The following description is provided to disclose the present application so that those skilled in the art can implement the present application. The preferred embodiments in the following description are only examples, and other obvious modifications can be made by those skilled in the art. The basic principles defined in the following description can be applied to other embodiments, modifications, improvements, equivalents, and other technical solutions without departing from the spirit and scope of the present application.

[0027] Those skilled in the art should understand that in the disclosure of the present application, the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate the orientation or positional relationship shown in the drawings, which are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore the above terms cannot be understood as a limitation of the present application.

[0028] It can be understood that the term "one" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of one element can be one, and in another embodiment, the number of the element can be multiple, and the term "one" cannot be understood as a limitation on the number. It can be understood that the term "one" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of one element can be one, and in another embodiment, the number of the element can be multiple, and the term "one" cannot be understood as a limitation on the number.

[0029] As Figure 1 shown, a shallow-buried large-section station roof construction process of the present application comprises the following steps:

[0030] Step S1, according to the site conditions and construction criteria, design construction drawings, wherein the cross section of the station front construction channel 100 is square, the cross section of the station main body 200 is semicircular, the station front construction channel 100 is located on the left side of the station main body 200, and the two intersect to form a station main body intersection 300;

[0031] Step S2, excavate the station front construction channel 100, and excavate the station main body at the bottom of the station front construction channel 100 with a slope of 22%, in the process, excavate the cross section at the station main body intersection;

[0032] Step S3, after excavating until reaching the vertical center line of the station main body, adjust the excavation slope 400 to a flat slope, continue to excavate to the right end of the station main body, and divide the station main body 200 into an upper cross section 210 and a lower cross section 220 along the slope line,

[0033] wherein during the excavation of the upper cross section 210, every 3 meters of excavation, a supporting steel truss is set at the excavated position, and steel structures are respectively set on the top surface, side surface and ground surface of the excavated position, and concrete is sprayed on the surface thereof to support the excavation cross section;

[0034] Step S4, after the upper cross section 210 is constructed to a preset distance L1, the lower cross section 220 is excavated, and during the excavation of the lower cross section, every 2 meters of excavation of the upper cross section 210, the corresponding supporting steel truss of the upper cross section 210 at the excavated position is lengthened, and steel structures are respectively set on both sides of the excavated position, and concrete is sprayed on the surface thereof to support the excavation cross section;

[0035] and the upper cross section excavation and the lower cross section excavation are kept in synchronization, and the two always maintain a preset distance L1,

[0036] until the excavation of the lower cross section is completed, at which time the support between the upper cross section and the lower cross section is removed.

[0037] The construction method in the above embodiment divides the entire station roof into sections for construction, and each section is excavated in blocks, which has high excavation stability and is not prone to collapse during excavation, and the construction speed is fast, greatly shortening the construction period.

[0038] Before construction, the site measurement personnel sets out the excavation contour line. During the whole excavation process, the non-explosive excavation is carried out by using the cantilever excavator. During the excavation process, the upper section 210 and the lower section 220 are staggered to be excavated, and the upper section 210 is excavated first. The upper section is excavated, and the steel truss and the sprayed concrete are set to support it to avoid collapse, so that the tunnel top still has great strength after being excavated.

[0039] It should be noted that before the step S3, the steel mesh is laid on the top before the supporting steel truss is set in the excavated part. The steel mesh is sprayed with C25 wet sprayed concrete, and the sprayed concrete has a thickness of 320 mm.

[0040] Preferably, during the construction process, the ground surface settlement of the tunnel peripheral soil, the vault settlement of the tunnel structure vault, the clearance convergence of the tunnel structure haunch, the structure stress at the stress concentration position and the end surface conversion position need to be periodically monitored and measured.

[0041] The early warning cumulative value of the ground surface settlement is 21 mm, the rate is 2.1 mm / d, the early warning cumulative value of the vault settlement of the tunnel structure vault is 14 mm, the rate is 2.1 mm / d, and the early warning cumulative value of the clearance convergence of the tunnel structure haunch is 21 mm, the rate is 2.1 mm / d.

[0042] It should be noted that the monitoring and measurement process in the step S4 is completed on the monitoring points on the monitoring section, the monitoring section is set at 5 meters before the excavation section, and the monitoring section is perpendicular to the center line of the excavation line. The monitoring points are multiple and uniformly distributed.

[0043] When one of the following conditions occurs, the monitoring frequency should be increased:

[0044] 1) The monitoring data reaches the alarm value; 2) The monitoring data changes greatly or the rate increases; 3) There are adverse geological conditions that are not found in the survey; 4) There is a large amount of water in the surrounding area, long-term continuous rainfall, municipal pipeline leakage; 5) The sudden increase or exceeding of the design limit value of the nearby ground load; 6) The sudden large settlement or serious cracking of the surrounding ground; 7) The sudden large settlement, uneven settlement or serious cracking of the adjacent building (structure); 8) Other abnormal conditions that affect the safety of the tunnel and the surrounding environment.

[0045] Preferably, during the excavation process of the upper section / lower section, the to-be-excavated section of the upper section / lower section is divided into a left side chamber and a right side chamber.

[0046] The left side chamber is excavated first, and during the excavation of the left side chamber, a supporting steel truss is set at every 4 meters in the excavated part, and a steel structure is set on the top surface, the side surface and the ground surface of the excavated part, and the surface is sprayed with concrete.

[0047] When the left side chamber is excavated to the preset length L2, the right side chamber is excavated, and every 4 meters, a supporting steel truss is arranged at the excavated position during the excavation of the right side chamber, and a steel structure is arranged on the top surface, side surface and ground surface of the excavated position respectively, and concrete is sprayed on the surface thereof;

[0048] The excavation of the left side chamber and the excavation of the right side chamber are kept synchronous, and the distance between the left side chamber and the right side chamber is always kept at the preset distance L2 until the excavation of the lower section is completed, and then the support between the left side chamber and the right side chamber is removed.

[0049] Thus, the right side chamber excavated later can also have a certain supporting effect during the excavation, reducing the risk of collapse, and the staggered distance of the left side chamber and the right side chamber is preferably controlled at L2, and the specific value of L2 can be determined according to the actual construction situation, if the distance is too long, it will seriously affect the construction efficiency, and if the distance is too short, the two chambers will be excavated almost at the same time, which will also result in poor supporting effect.

[0050] Preferably, in the step S4, the bottom of the supporting steel truss after the lengthening treatment is supported on a hard platform, the strength of the hard platform exceeds a preset strength, preventing the arch support from sinking, and also avoiding the damage of the supporting steel truss to the bottom soil layer.

[0051] Preferably, in the step S2, at the station main body intersection, the section will change from a portal section to an arch section, and the process adopts a rock drill combined with a boom jumbo for excavation operation, and manual adjustment is performed during the process until the arch section is formed.

[0052] Preferably, in the step S4, the steel truss at the station main body intersection needs to be reinforced during the excavation of the section at the station main body intersection, because the stress condition at the station main body intersection is relatively complex.

[0053] Although the embodiments of the present application have been disclosed as above, they are not limited to the application and implementation listed in the specification and embodiments, and can be fully applied to various fields suitable for the present application, and other modifications can be easily realized by those skilled in the art, and therefore the present application is not limited to specific details and the figures shown and described herein, without departing from the general concept defined by the claims and the equivalent scope.

Claims

1. A construction technique for the cantilevered roof of a shallow-buried, large-section tunnel railway station, characterized in that, Includes the following steps: Step S1: Design construction drawings based on site conditions and construction guidelines. The cross-section of the construction access road in front of the station is square, and the cross-section of the main station body is semi-circular. The construction access road in front of the station is located on the left side of the main station body, and the two intersect to form the station body intersection. Step S2: Excavate the construction passage in front of the station, with the bottom slab of the construction passage facing the main body of the station at a slope of 22%. During this process, the excavation will form a cross section at the intersection of the main body of the station. Step S3: Continue excavation until the vertical centerline of the station's main structure is reached. Adjust the excavation slope to a level slope and continue excavating to the right end of the station's main structure. Divide the station's main structure into upper and lower sections along the slope line. During the excavation of the upper section, a support steel truss is set up at the excavated area every 3 meters. Steel structures are also set up on the top, sides and ground of the excavated area, and concrete is sprayed on their surfaces to support the excavated section. Step S4: After the upper section is constructed to the preset distance L1, the lower section excavation begins. During the lower section excavation, every 2 meters of the upper section is excavated, the corresponding support steel truss of the upper section is extended at the excavated area. Steel structures are then set up on both sides of the excavated area, and concrete is sprayed onto their surfaces to support the excavated section. Furthermore, the excavation of the upper and lower sections should be carried out simultaneously, and the two sections should always maintain a preset distance L1. Continue until the excavation of the lower section is completed, at which point the supports between the upper and lower sections are removed. During construction, it is necessary to monitor and measure the surface settlement of the soil around the tunnel, the crown settlement of the tunnel structure, the net clearance convergence of the tunnel structure's waist and the structural stress at the end face transition points and stress concentration points. During the excavation of the upper / lower sections, the sections to be excavated in the upper / lower sections are divided into the left-side chamber and the right-side chamber. Cavern; First, excavate the left-side tunnel. During the excavation of the left-side tunnel, every 4 meters, a support steel truss is set up at the excavated area. Steel structures are set up on the top, sides and ground of the excavated area, and concrete is sprayed onto their surfaces. When the excavation reaches the preset length L2, the excavation of the right-side tunnel begins. During the excavation of the right-side tunnel, a support steel truss is set up every 4 meters at the excavated area. Steel structures are also set up on the top, sides and ground of the excavated area, and concrete is sprayed onto their surfaces. The excavation of the left and right caverns should be carried out simultaneously, and the two should always maintain a preset distance L2 until the excavation of the lower section is completed. At this point, the support between the left and right caverns should be removed.

2. The construction technology for the cantilevered roof of a shallow-buried, large-section tunnel station according to claim 1, is characterized in that, In step S1, before construction, the excavation outline is laid out, and a cantilever tunneling machine is used for non-explosive excavation.

3. The construction technology for the cantilevered roof of a shallow-buried, large-section tunnel station according to claim 1, is characterized in that... In step S4, the bottom of the extended support steel truss is supported on a rigid platform, the strength of which exceeds a preset strength.

4. The construction technology for the cantilevered roof of a shallow-buried, large-section tunnel station according to claim 2, is characterized in that, In step S4, the monitoring and measurement process is completed at the monitoring points on the monitoring section. The monitoring section is set 5 meters in front of the excavation section and is perpendicular to the centerline of the excavation line. There are multiple monitoring points.

5. The construction technology for the cantilevered roof of a shallow-buried, large-section tunnel station according to claim 1, characterized in that, In step S2, at the main intersection of the station, the cross-section will change from a portal cross-section to an arch cross-section. This process is carried out by using a rock drill in conjunction with a cantilever tunneling machine.

6. The construction technology for the cantilevered roof of a shallow-buried, large-section tunnel station according to claim 5, is characterized in that... In step S4, when excavating the cross section at the intersection of the main station structure, the steel truss at this location needs to be reinforced.

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