CN109736843B - A kind of retrograde waterproofing method of assembling and pouring secondary lining with small formwork - Google Patents

Abstract

The invention relates to a reverse waterproof method for assembling and pouring a secondary lining by a small template, belonging to the technical field of tunnel construction; after lagging behind the upper section of the top right pilot tunnel and the upper section of the top left pilot tunnel by a certain distance, excavating the lower end surface of the top right pilot tunnel and the lower section of the top left pilot tunnel; excavating an upper section of the middle right pilot tunnel, an upper section of the middle left pilot tunnel, a lower end surface of the middle right pilot tunnel and a lower section of the middle left pilot tunnel; and excavating the upper section of the bottom right pilot tunnel, the upper section of the bottom left pilot tunnel, the lower section of the bottom right pilot tunnel and the lower section of the bottom left pilot tunnel by using a step method, wherein the left side and the right side are crossed. The waterproof difficult problem of construction face kneck about solving for the construction progress improves secondary lining's quality, guarantees the safe quick construction of cross access and even station main tunnel.

Description

A kind of retrograde waterproofing method of assembling and pouring secondary lining with small formwork

technical field

The invention relates to the technical field of tunnel construction, in particular to a reverse working waterproof method for assembling and pouring a secondary lining with a small formwork.

Background technique

Construction of large-span underground tunnels in narrow sites is a common problem in the construction of urban subway stations. Due to site conditions, subway stations often use horizontal passages to transfer into the main tunnel for construction. Therefore, the safe and rapid construction of the horizontal passage is of great significance to save the construction period of the subway station. After the excavation of the transverse channel, in order to maintain the stability of the surrounding rock, initial support and lining are generally required. During actual construction, due to the consideration of construction period and excavation risk management, the secondary lining may need to be poured in sections and then closed into a ring. In areas with abundant groundwater, the quality of the project is seriously affected.

SUMMARY OF THE INVENTION

The purpose of the present invention is to aim at the defects and deficiencies of the prior art, to provide a simple structure, reasonable design and convenient use of a small formwork assembling and pouring a reverse waterproofing method for the secondary lining, so as to solve the problem of waterproofing at the interface of the upper and lower construction surfaces and speed up the construction progress. , improve the quality of the secondary lining, and ensure the safe and rapid construction of the cross passage and even the main tunnel of the station.

To achieve the above object, the technical scheme adopted in the present invention is: its construction method is as follows:

1. Use the steel frame erected in the previous cycle to apply the Ф42 grouting small duct on the side wall of the tunnel; use the CD method to excavate the upper section of the top right guide pit and the upper section of the top left guide pit; spray the closed face; apply the top The initial support and temporary support around the guide pit on the upper section of the right guide pit, that is, the initial spraying of 4CM thick concrete, the laying of steel mesh, the erection of section steel frame and I20a temporary steel frame, and the setting of locking anchors and positioning steel bars; After setting the system bolt, re-spray concrete to the design thickness; after a certain distance behind the upper section of the top right pilot pit and the upper section of the top left pilot pit, excavate the lower end face of the top right pilot pit and the lower section of the top left pilot pit;

2. After the arch is excavated and supported for 20 meters, the waterproof system treatment and secondary pouring of the upper section of the top right pilot pit and the upper section of the top left pilot pit are carried out;

3. Use the step method to excavate the upper section of the middle right pilot pit, the upper section of the left pilot pit in the middle, the lower end face of the middle right pilot pit and the lower section of the middle left pilot pit. When the length is greater than 15m, carry out the secondary lining waterproofing, reinforcing bars and pouring operations of the middle side wall on one side. After the previous pouring strength reaches 70%, carry out the secondary lining casting operation of the middle side wall on the other side;

4. Use the step method to excavate the upper section of the bottom right pilot pit, the upper section of the bottom left pilot pit, the lower section of the bottom right pilot pit and the lower section of the bottom left pilot pit. The left and right sides are crossed. When the construction length is greater than 10m, the Perform the second lining pouring operation of the bottom arch, and then carry out the second lining waterproofing, reinforcing bars, and pouring operations of the bottom side wall on one side. The secondary lining pouring operation of the side wall.

Further, in the step 2, the secondary lining concrete is poured for 20 meters at one time, and after the strength reaches 70%, the excavation of the lower side of the pouring section is carried out.

Further, the casting of the middle side wall in the step 3 is controlled within a range of 5 meters, and the casting of the remaining side walls is controlled within a range of 15 meters.

Further, the pouring in the steps 3 and 4 adopts the mode of integral pouring, and the construction technology is followed by the method, and the pouring length is controlled within the range of 10 meters.

Further, in the excavation process of the described steps 1 to 4, when encountering the joint of the second lining concrete, the weak blasting excavation of the middle groove is carried out first, and the side wall adopts the construction of weak blasting, carbon dioxide cracking and cold opening. technology, strengthen the protection of the mortar rubble, and completely eliminate the impact of blasting on the completed secondary lining.

After the above structure is adopted, the beneficial effects of the present invention are as follows: the retrograde waterproofing method for assembling and pouring the secondary lining with a small formwork according to the present invention solves the problem of waterproofing at the interface of the upper and lower construction surfaces, accelerates the construction progress, and improves the quality of the secondary lining, To ensure the safe and rapid construction of the transverse passage and even the main tunnel of the station, the invention has the advantages of simple structure, reasonable setting, low production cost and the like.

Description of drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained according to these drawings without creative efforts.

Figure 1 is a schematic sectional view of the present invention.

Figure 2 is a construction elevation view of the upper section of the top right guide pit and the upper section of the top left guide pit in the present invention.

Figure 3 is a construction plan view of the upper section of the top right guide pit and the upper section of the top left guide pit in the present invention.

4 is a construction elevation view of the upper section of the middle right pilot pit and the upper section of the middle left pilot pit of the present invention.

5 is a construction plan view of the upper section of the middle right pilot pit and the upper section of the middle left pilot pit in the present invention.

Fig. 6 is the construction elevation view of the upper section of the bottom right guide pit and the upper section of the bottom left guide pit in the present invention.

7 is a construction plan view of the upper section of the bottom right guide pit and the upper section of the bottom left guide pit in the present invention.

FIG. 8 is a drawing of the steel bar joint at the construction joint and the construction measures for waterproof treatment in the present invention.

FIG. 9 is a drawing of the construction measures for the treatment of incompact concrete pouring of construction joints in the present invention.

Description of reference numbers:

Top right pilot pit upper section 1, top right pilot pit bottom face 1-1, top left pilot pit upper section 2, top left pilot pit lower section 2-1, middle right pilot pit upper section 3, middle right pilot pit lower end face 3-1. There is an upper section of the left guide pit in the middle section 4, a lower section of the left guide pit in the middle section 4-1, an upper section of the bottom right guide pit 5, a lower section of the bottom right guide pit 5-1, an upper section of the bottom left guide pit 6, the bottom Left pilot pit lower section 6-1, top arch 7, middle side wall 8, bottom side wall 9, bottom arch 10, lining formwork 11, grout rubble 12, waterproof board 13, steel plate 14, grouting pipe 15.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings.

Referring to Fig. 1-Fig. 9, this specific embodiment is applied and implemented in the construction of the horizontal passage of the wind pavilion on the No. 2 Guanshui Road Station of Guiyang Rail Transit Line 2#. No. 2 wind pavilion at Guanshui Road Station is located in the residential area on the left side of the left tunnel in the section between Guanshui Road Station and YDK36+300. The middle line of the cross passage intersects the route at the mileage of ZDK36+136.287. The cross passage is connected to the main hole and is orthogonal to the main hole. . The clearance size in the shaft of No. 2 wind pavilion is 6.6*15m, and the well depth is 32.998m; the length of the horizontal passage is 51.03m, and the excavation width*height=12.26*18.293m. , red clay, dolomite of the Lower Triassic Anshun Formation, the wellbore is mainly located in the dolomite; the depth of the top arch of the transverse channel is 14.7-16.5m, and the thickness of the vault bedrock is 0.3-4.2m.

The construction method of this specific embodiment is as follows:

1. Use the steel frame erected in the previous cycle to apply the Ф42 grouting small pipe on the side wall of the tunnel; use the CD method to excavate the upper section 1 of the top right pilot pit and the upper section 2 of the top left pilot pit; spray the closed tunnel face; For the initial support and temporary support around the guide pit on the upper section of the right guide pit at the top, that is, initial spraying of 4CM thick concrete, laying steel mesh, erecting profiled steel frame and I20a temporary steel frame, and setting up locking anchors and positioning Reinforcing bars; re-spray concrete to the design thickness after setting the system bolt; after a certain distance behind the top right pilot pit upper section 1 and the top left pilot pit upper section 2, excavate the lower end face 1-1 of the top right pilot pit and the top left pilot pit The lower section of the guide pit is 2-1;

2. After the arch is excavated and supported for 20 meters, install the multi-functional assembly trolley for the second lining of the arch, and design a plan for small formwork assembly to pour the concrete of the top arch 7;

3. Use the step method to excavate the upper section 3 of the middle right pilot pit, the upper section 4 of the left pilot pit in the middle, the lower end face 3-1 of the middle right pilot pit and the lower section 4-1 of the middle left pilot pit, and the left and right crossing operations. The secondary lining is staggered before and after the pouring operation. When the construction length is greater than 15m, the secondary lining waterproofing, reinforcing bars and pouring operations of the middle side wall 8 on one side are performed. After the previous casting strength reaches 70%, the secondary lining casting of the middle side wall 8 on the other side is performed. Operation;

4. Use the step method to excavate the upper section 5 of the bottom right pilot pit, the upper section 6 of the bottom left pilot pit, the lower section 5-1 of the bottom right pilot pit and the lower section 6-1 of the bottom left pilot pit, and the left and right sides are crossed. , when the construction length is greater than 10m, perform the second lining pouring operation of the bottom arch 10, and then carry out the second lining waterproofing, reinforcing bars, and pouring operations of the unilateral bottom side wall 9. The second lining pouring operation is staggered before and after, that is, the current casting strength After reaching 70%, the secondary lining pouring operation of the bottom side wall 9 on the other side is carried out.

Further, in the step 2, the secondary lining concrete is poured for 20 meters at one time, and after the strength reaches 70%, the excavation of the lower side of the pouring section is carried out.

Further, the casting of the middle side wall 8 in the step 3 is controlled within a range of 5 meters, and the casting of the remaining side walls is controlled within a range of 15 meters.

Further, the pouring in the steps 3 and 4 adopts the mode of integral pouring, and the construction technology is followed by the method, and the pouring length is controlled within the range of 10 meters.

Further, in the excavation process of the described steps 1 to 4, when encountering the joint of the second lining concrete, the weak blasting excavation of the middle groove is carried out first, and the side wall adopts the construction of weak blasting, carbon dioxide cracking and cold opening. technology, strengthen the protection of the mortar rubble, and completely eliminate the impact of blasting on the completed secondary lining.

Further, the construction joints of the described top arch 7, the middle side wall 8, the bottom side wall 9 and the bottom arch 10 need to carry out steel bar joints and waterproof treatment, and the process is as follows: before the concrete pouring of the top arch 7, Reserving steel bars, laying formwork 11 at the bottom and sides, and laying rubble 12 under formwork 11 to the bedrock surface. Before pouring the middle side wall 8, complete the protection and reinforcement of the rubble 12 (if necessary, hang the net to spray concrete), The upper and lower steel bars are connected by connectors, and the waterproof plate 13 is protected by filling fine sand and will not be damaged. The steel plate above the mortar rubble 12 is set at a 10% inclination angle, and the secondary lining after forming will be "low outside and high inside" , help prevent groundwater backflow.

Further, the construction joint waterstops at the construction joints of the top arch 7, the middle side wall 8, the bottom side wall 9 and the bottom arch 10 are pre-buried and can be wrapped around the grouting pipe 15, and the backfill cement slurry is taken. The grouting pipe is arranged horizontally and vertically, and the two ends of the grouting pipe lead out of the pouring surface, the purpose is to make the overall connection dense.

The Φ42 grouting small duct in this specific embodiment has a wall thickness of 4.0 mm, L=3.5 m, a circumferential spacing of 0.35 m, a longitudinal spacing of 1.5 m, an outer gusset angle of 5 to 7°, and the overlapping length of the small duct is not less than 1 m. The stratum is reinforced by grouting. The excavation footage of each excavation is 0.5m. During excavation, it is strictly forbidden to excavate the bottom. The excavation is carried out layer by layer from top to bottom. concrete. Steel frame: I25b steel frame is set in full ring, with a spacing of 0.5m/square. System bolt: The arch adopts Φ32 grouting steel flower tube, the outer angle is 60°, the longitudinal spacing of the ring is 1.0*1.0m, the plum blossom-shaped arrangement, L=3.5m, the wall thickness is 3mm, and the front part is drilled with grouting holes, with a diameter of 6 ~8mm, the hole spacing is 20cm, and a grouting section of not less than 30cm is reserved at the tail. The grouting parameters of the Φ32 grouting steel flower tube are handled with reference to the grouting parameters of the advanced small pipe; the side wall adopts the Φ22 mortar bolt, L=4.5m; Spacing: 1.0*1.0m (ring*longitudinal), plum-shaped arrangement. Reinforcement mesh: Φ8 steel bars, forming a 20*20cm grid, set in a full ring; the reinforcement mesh should be firmly welded to the end of the anchor rod.

After adopting the above structure, the beneficial effects of this specific embodiment are:

After the excavation of the horizontal passage, the existing technology is to carry out secondary lining after the completion of the construction of the station and section tunnels. However, in the actual construction process, the excavation risk of each excavation step may be relatively large, and the construction period is short. When the secondary lining must be poured in sections and time-sharing, the corresponding waterproof measures are too simple and cannot solve the upper and lower construction well. To solve the problems of seepage and water leakage at the surface interface, the present invention combines the on-site construction experience, fully considers the construction practice, and proposes a new waterproof method based on the traditional construction method to solve the shortcomings of the existing technology.

The above is only used to illustrate the technical solution of the present invention and not to limit it. Other modifications or equivalent replacements made by those of ordinary skill in the art to the technical solution of the present invention, as long as they do not depart from the spirit and scope of the technical solution of the present invention, should be Included within the scope of the claims of the present invention.

Claims (1)

1. A reverse waterproof method for assembling and pouring a second lining by a small template is characterized by comprising the following steps: the construction method comprises the following steps:

(1) constructing a small grouting guide pipe on the side wall phi 42 of the tunnel by using the steel frame erected in the previous cycle; excavating an upper section of the top right pilot tunnel and an upper section of the top left pilot tunnel by using a CD method; spraying a closed palm surface; constructing primary support and temporary support at the periphery of the guide pit of the upper section of the right guide pit at the top, namely initially spraying 4CM thick concrete, laying a steel bar mesh, erecting a steel frame and an I20a temporary steel frame, and arranging a foot locking anchor rod and a positioning steel bar; after setting a system anchor rod, re-spraying concrete to the designed thickness; after lagging behind the upper section of the top right pilot pit and the upper section of the top left pilot pit by a certain distance, excavating the lower end face of the top right pilot pit and the lower section of the top left pilot pit, in the excavating process, when meeting the joint of the two linings of concrete, firstly performing weak blasting excavation of a middle groove, and adopting the construction process of weak blasting, carbon dioxide presplitting and cold opening on a side wall to strengthen the protection of the grouted rubble and completely avoid the influence of blasting on the completed two linings;

(2) after arch excavation supporting and forming is carried out for 20 meters, waterproof system treatment and secondary pouring operation of the upper section of the right pilot tunnel at the top and the upper section of the left pilot tunnel at the top are carried out, secondary lining concrete is poured for 20 meters at one time, after the strength reaches 70%, excavation of one side of the lower part of a pouring section is carried out, in the excavation process, when the joint of the secondary lining concrete is met, weak blasting excavation of a middle groove is carried out firstly, and the side wall adopts the construction processes of weak blasting, carbon dioxide presplitting and cold opening, so that the protection of grouted rubble stones is enhanced, and the influence of blasting on the completed secondary lining is completely avoided;

(3) excavating the upper section of the middle right pilot tunnel, the upper section of the middle left pilot tunnel, the lower end surface of the middle right pilot tunnel and the lower section of the middle left pilot tunnel by using a step method, controlling the pouring of the middle side wall within the range of 5 meters, controlling the pouring of the other side walls within 15m, performing left-right cross operation, staggering the front and back of the second lining pouring operation, performing the second lining waterproof, reinforcing steel bar and pouring operation of the middle side wall on one side when the construction length is more than 15m, and after the previous pouring strength reaches 70%, performing secondary lining pouring operation of the side wall at the middle part of the other side, wherein the pouring adopts an integral pouring mode and a sequential construction method, the pouring length is controlled within 10 meters, and when a joint of secondary lining concrete is encountered in the excavation process, weak blasting excavation of the middle groove is firstly carried out, and the side wall adopts the construction processes of weak blasting, carbon dioxide presplitting and cold cracking, so that the protection of the grouted rubble is enhanced, and the influence of blasting on the finished secondary lining is completely avoided;

(4) excavating the upper section of the bottom right pilot tunnel, the upper section of the bottom left pilot tunnel, the lower section of the bottom right pilot tunnel and the lower section of the bottom left pilot tunnel by using a step method, performing crossed construction on the left side and the right side, performing secondary lining pouring operation on the arch part of the bottom when the construction length is more than 10m, then carrying out two-lining waterproof, reinforcing steel bar and pouring operation of the side wall at the bottom of the single side, wherein the two-lining pouring operation is staggered from front to back, namely, after the current casting strength reaches 70%, the two-lining casting operation of the bottom side wall at the other side is carried out, the casting adopts an integral casting mode, the construction process is carried out by a sequential method, the casting length is controlled within 10 meters, when the joint of the two-lining concrete is encountered in the excavation process, weak blasting excavation of the middle groove is firstly carried out, and the side wall adopts the construction processes of weak blasting, carbon dioxide presplitting and cold cracking, so that the protection of the grouted rubble is enhanced, and the influence of blasting on the finished secondary lining is completely avoided.

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