阅读说明：本技术 一种适用于近接扩挖隧道施工对既有隧道防护的施工方法 (Construction method suitable for protecting existing tunnel in close-proximity expanded excavation tunnel construction ) 是由 李正文 朱金砣 张积华 阮辉煌 甘歆洁 王庆龙 于 2019-08-26 设计创作，主要内容包括：本发明公开了一种适用于近接扩挖隧道施工对既有隧道防护的施工方法,包括以下步骤：准备原材料,同时对既有隧道进行基础的清理整平；将拱架安装台车紧贴既有隧道衬砌表面,沿隧道延伸方向安装拱架；在所述拱架贴近既有隧道衬砌的一面安装防护网,所述防护网沿所述拱架弧度且紧贴所述拱架安装,同时,相邻的所述拱架之间连接钢筋,所述拱架、防护网和钢筋形成防护棚架；检查所述防护棚架与既有隧道衬砌的密贴情况,对无法密贴部位采用填充物楔紧。通过由拱架、防护网、连接钢筋组成的防护棚架对既有隧道形成一个整体的防护结构,可有效防止拱顶掉块伤及车辆和行人,保证了既有通车隧道的行车安全性。(the invention discloses a construction method suitable for protecting an existing tunnel in the construction of a proximity expanded excavation tunnel, which comprises the following steps: preparing raw materials, and simultaneously cleaning and leveling the foundation of the existing tunnel; tightly attaching an arch center mounting trolley to the surface of the existing tunnel lining, and mounting an arch center along the extending direction of the tunnel; installing a protective net on one surface of the arch frame close to the existing tunnel lining, wherein the protective net is installed along the radian of the arch frame and close to the arch frame, meanwhile, reinforcing steel bars are connected between the adjacent arch frames, and the arch frame, the protective net and the reinforcing steel bars form a protective shed frame; and checking the tight adhesion condition of the protective shed frame and the existing tunnel lining, and wedging the parts which cannot be tightly adhered by adopting fillers. The protective shed frame consisting of the arch frame, the protective net and the connecting steel bars forms an integral protective structure for the existing tunnel, can effectively prevent the arch crown from dropping blocks to hurt vehicles and pedestrians, and ensures the driving safety of the existing traffic tunnel.)

1. A construction method suitable for protecting an existing tunnel in the construction of a proximity expansion excavation tunnel is characterized by comprising the following steps:

S1, construction preparation: preparing raw materials, and simultaneously cleaning and leveling the foundation of the existing tunnel;

S2, arch center installation: tightly attaching an arch center mounting trolley to the surface of the existing tunnel lining, and mounting an arch center along the extending direction of the tunnel;

s3, installing a protective net and reinforcing steel bars: installing a protective net on one surface of the arch frame close to the existing tunnel lining, wherein the protective net is installed along the radian of the arch frame and close to the arch frame, meanwhile, reinforcing steel bars are connected between the adjacent arch frames, and the arch frame, the protective net and the reinforcing steel bars form a protective shed frame;

S4, filling and reinforcing: and checking the tight adhesion condition of the protective shed frame and the existing tunnel lining, and wedging the parts which cannot be tightly adhered by adopting fillers.

2. The construction method as claimed in claim 1, wherein the raw materials include section steel, reinforcing steel, twisted steel, steel plate, bolts and the fillers in step S1, and the preparing of the raw materials includes designing an arch size according to an existing tunnel section profile, machining the arch, and assembling an arch installing trolley according to the designed size.

3. The construction method according to claim 2, wherein the arch installing trolley is formed by welding I-steel.

4. The construction method according to claim 1, wherein in step S1, the concrete steps of cleaning and leveling are as follows: cleaning and cleaning the arch foot positions on two sides of the existing tunnel, and leveling by using quick-drying cement.

5. the construction method according to claim 1, wherein in step S2, when the arches are installed, the installation distance between adjacent arches is 100cm, and plumb line is used to ensure the verticality of the arches according to the measurement lofting point.

6. The construction method according to claim 1, wherein in step S3, the protection net is formed by inserting HPB300 Φ 6 steel bars, the size of the net of the protection net is 5 x 5cm, and not less than 2 nets are lapped between adjacent protection nets.

7. the construction method according to claim 1, wherein in step S3, the reinforcing bars are HRB400 Φ 22 reinforcing bars, and the circumferential distance between the reinforcing bars installed between adjacent arches of the same segment is 100 cm; and the adjacent reinforcing steel bars are transversely staggered by 50cm along the extending direction of the tunnel.

8. The construction method according to claim 1, wherein in step S4, the filler is a light wood block fixed on the i-steel of the arch.

Technical Field

The invention belongs to the technical field of tunnel engineering construction, and particularly relates to a construction method suitable for protecting an existing tunnel in the construction of a proximity expansion excavation tunnel.

Background

Tunnels are engineering structures buried in the ground and are a form of human use of underground space. With the increase of population and the development of urbanization, land resources are increasingly in short supply, the requirement of human beings on the environment is higher and higher, the characteristic that the tunnel is positioned underground can effectively save land, and the tunnel becomes a good choice by protecting the environment. Meanwhile, with the generalization of underground space utilization, the tunnel can ensure driving safety, shorten the driving range, avoid disasters and other advantages and also promote the tunnel construction technology to generate qualitative changes.

urban tunnels and most highway tunnels are arranged by adopting uplink and downlink double tunnels, and with the development of times, the transportation capacity of the tunnels becomes a bottleneck restricting traffic in large and medium-sized cities with dense population or expressways with huge traffic flow. In the face of increasingly severe traffic problems, the reconstruction and expansion of the existing tunnel to meet the traffic requirements has become a necessary choice for infrastructure in some places.

In the places with dense population and huge traffic flow, most tunnel expansion excavation modification needs to adopt unilateral closed expansion excavation under the condition that the unilateral guarantees the traffic, but the tunnel expansion excavation is also difficult to ensure the driving safety of the adjacent tunnel.

disclosure of Invention

in view of the above, the present invention needs to provide a construction method for protecting an existing tunnel in a tunnel near-proximity enlarging excavation construction, which is used for leveling the position of the arch springing of the existing tunnel, so as to bear the load transmitted by the steel arch, and simultaneously, a protective shed frame is formed in the tunnel, so as to prevent the arch crown from dropping and damaging vehicles and pedestrians, and fillers are filled in the gap between the protective shed frame and the tunnel lining, so as to ensure the reasonable stress of the steel arch frame, thereby solving the technical problem of how to ensure the driving safety of the adjacent tunnel in the tunnel near-proximity enlarging excavation.

In order to achieve the purpose, the invention adopts the following technical scheme:

A construction method for protecting an existing tunnel suitable for construction of a close-proximity expanded excavation tunnel comprises the following steps:

S1, construction preparation: preparing raw materials, and simultaneously cleaning and leveling the foundation of the existing tunnel;

S2, arch center installation: tightly attaching an arch center mounting trolley to the surface of the existing tunnel lining, and mounting an arch center along the extending direction of the tunnel;

S3, installing a protective net and reinforcing steel bars: installing a protective net on one surface of the arch frame close to the existing tunnel lining, wherein the protective net is installed along the radian of the arch frame and close to the arch frame, meanwhile, reinforcing steel bars are connected between the adjacent arch frames, and the arch frame, the protective net and the reinforcing steel bars form a protective shed frame;

s4, filling and reinforcing: and checking the tight adhesion condition of the protective shed frame and the existing tunnel lining, and wedging the parts which cannot be tightly adhered by adopting fillers.

further, in step S1, the raw material includes section steel, reinforcing steel, twisted steel, steel plate, bolt, and the filler, and the preparing raw material includes designing the size of the arch according to the profile of the existing tunnel section, machining the arch, and assembling the arch installation trolley according to the designed size.

Preferably, the arch center mounting trolley is formed by welding I-steel.

Further, in step S1, the specific steps of cleaning and leveling include: cleaning and cleaning the arch foot positions on two sides of the existing tunnel, and leveling by using quick-drying cement.

further, in step S2, when the arches are installed, the installation distance between adjacent arches is 100cm, and plumb line is adopted according to the measurement lofting point to ensure the perpendicularity of the arches.

Further, in step S3, the protection net is formed by inserting HPB300 Φ 6 steel bars, the size of the meshes of the protection net is 5 × 5cm, and not less than 2 meshes are lapped between adjacent protection nets. Specifically, the protection net is formed by inserting longitudinal steel bars and transverse steel bars, the size of the formed grid is 5 x 5cm, the protection net is installed between adjacent arches, the adjacent protection nets are lapped, and the lapping is that the overlapped part is not less than 2 grids.

further, in step S3, the reinforcing steel bars are HRB400 Φ 22 reinforcing steel bars, and the circumferential distance between the reinforcing steel bars installed between adjacent arches of the same segment is 100 cm; and the adjacent reinforcing steel bars are transversely staggered by 50cm along the extending direction of the tunnel. Specifically, in the staggered arrangement of the reinforcing bars, if the first connecting reinforcing bar is installed between the first arch and the second arch from the position 1m above the arch foot, the position of the first connecting reinforcing bar between the second arch and the third arch should be at the position 50cm above the arch foot, and the first connecting reinforcing bar and the second connecting reinforcing bar alternate.

further, in step S4, the filler is a light wood block, and the light wood block is fixed on the i-steel of the arch center.

The invention has the advantages that the protective shed frame consisting of the arch frame, the protective net and the connecting steel bars forms an integral protective structure for the existing tunnel, can effectively prevent the arch crown from dropping blocks to hurt vehicles and pedestrians, and ensures the driving safety of the existing traffic tunnel; in addition, the arch springing positions on two sides of the existing tunnel are leveled in advance, so that the load transmitted by the steel arch frame is well borne, and the safety in the tunnel is further guaranteed; the construction method is simple and high in safety, and is very suitable for protection of the existing tunnel in the construction of the proximity expanded excavation tunnel.

drawings

FIG. 1 is a schematic elevational view of a shelter frame according to a preferred embodiment of the present invention;

FIG. 2 is an enlarged schematic view of the shelter frame 20 of FIG. 1;

FIG. 3 is a side schematic view of the shelter frame 20 of FIG. 1;

Fig. 4 is a schematic top view of the anti-slip canopy frame 20 shown in fig. 1.

In the figure: 10-existing tunnel, 20-protective shed frame, 21-arch frame, 22-protective net, 23-light wood block and 24-reinforcing steel bar.

Detailed Description

In order that the invention may be more fully understood, reference will now be made to the specific embodiments illustrated. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

A construction method for protecting an existing tunnel suitable for near-proximity expanded excavation tunnel construction specifically comprises the following steps:

S1, construction preparation: preparing raw materials including section steel, reinforcing steel bars, thread reinforcing steel bars, steel plates, bolts and light wood blocks, and designing the size of an arch frame 21 according to the profile of the section of the existing tunnel 10, wherein the arch frame 21 is a steel arch frame and is welded by I14I-steel, and one arch frame comprises an arc top frame and straight legs welded at two ends of the arc top frame, and in the embodiment, the arc top frame is formed by welding 3 arcs with the outer arc radius of 4.55m and the outer arc length of 4.3m, and the length of the straight legs is 2.75 m; meanwhile, the size of the trolley is designed according to the section of the inner contour of the existing tunnel lining, and the trolley (not shown) is installed by splicing and welding H-shaped steel arches. In addition, cleaning and leveling are carried out on site, specifically, as the tunnel reinforced steel arch is supported on the cable trench and the maintenance channel, and the surface part of the power trench and the maintenance channel is flat due to damage and the like, and the power trench and the maintenance channel cannot bear the load transmitted by the steel arch, the cable trench maintenance channels on two sides and the arch springing positions on two sides are cleaned and leveled with quick-drying mortar before the arch 21 is installed, in the embodiment, the preferred quick-drying mortar is M30 quick-drying mortar, so that the foundation can be uniformly stressed after the arch 21 is installed;

s2, positioning an arch center mounting trolley: the arch installing trolley is tightly attached to the surface of the existing tunnel lining to install the arches 21, when the arch installing trolley is installed, the installation distance between the adjacent arches 21 is 100cm, the arches 21 are bolted by adopting 200 multiplied by 180 multiplied by 16mm thick steel plates and M24 multiplied by 60AM bolts, the arches 21 are connected along the extending direction of the tunnel by adopting HRB400 phi 22 steel bars 24, the steel bars 24 installed between the same adjacent arches 21 are 100cm along the arc direction of the arches 21, the longitudinally adjacent steel bars 24 are transversely staggered by 50cm to reinforce the arch 21 connection, the perpendicularity of the arches 21 is ensured, specifically, a total station is adopted to measure and sample out the point of the same mileage section of the tunnel on the center line of the arch, the arch waists on two sides and the straight legs on the two sides, the arch 21 is ensured to be installed on the same vertical section through the 5 points, a center can be released on the tunnel pavement opposite to the center line of the arch, the plumb is hung from the center point of the vault to the center point of the ground, and the distance from the plumb line to the arch centering 21 at two sides is measured by a box ruler, so that whether the arch centering 21 is vertical or not can be checked;

S3, installing a protective net and reinforcing steel bars: after the arch 21 is installed, installing a protective net 22 on the face, close to the existing tunnel 10 lining, of the arch 21, wherein the protective net 22 is tightly attached to the arch 21, in this embodiment, the protective net 22 is formed by inserting and welding HPB300 Φ 6 steel bars in the longitudinal direction and the transverse direction, the specification of grids is 5 × 5cm, no less than two grids are lapped between the adjacent protective nets 22, and the firmness of the safety net is ensured, as shown in fig. 3; meanwhile, the arch 21 is connected with the reinforcing steel bars 24 along the extending direction of the tunnel, the reinforcing steel bars 24 are HRB400 phi 22 reinforcing steel bars, the circumferential arrangement is between the adjacent arch 21, the distance is 100cm, and the transverse staggering is 50cm between the adjacent reinforcing steel bars 24 along the extending direction (longitudinal direction) and the longitudinal direction of the tunnel, as shown in FIG. 4, if a first reinforcing steel bar is installed between a first arch and a second arch from the position of 1m above the arch, the position of the first reinforcing steel bar between the second arch and a third arch should be the position of 50cm above the arch, so that the first reinforcing steel bar and the second reinforcing steel bar are alternated. Thus, the arch 21, the protection net 22, and the reinforcing bars 24 form the protection canopy frame 20 closely attached to the existing tunnel lining 10, as shown in fig. 1.

S4, filling and reinforcing: checking the close contact between the protective shed frame 20 and the existing tunnel lining 10, and wedging the parts that cannot be close contact with each other with a filler, wherein in the present embodiment, the filler is a light wood block 23, as shown in fig. 2, the light wood block 23 is specifically fixed on the i-steel of the arch frame 21, specifically, in the present embodiment, an iron wire is sleeved on the light wood block 23, and the light wood block 23 is fixed on the i-steel of the arch frame 21 through the iron wire.

By the construction method, an integral protective structure can be formed for the existing tunnel 10, and the driving safety of the existing traffic tunnel is ensured.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.