阅读说明：本技术 一种隧道内跨越溶洞的钢混组合拱桥及其施工方法 (Steel-concrete combined arch bridge crossing karst cave in tunnel and construction method thereof ) 是由 李玲玉 黄灿 陈松洲 于 2020-08-10 设计创作，主要内容包括：本发明提供一种隧道内跨越溶洞的钢混组合拱桥及其施工方法,拱桥包括多根并列设置的型钢拱肋,每根型钢拱肋的两端与浇筑在溶洞两侧壁上的拱座固定连接,相邻型钢拱肋间有一定间距,并通过多根横梁连接,所述横梁上铺设有支撑钢板,钢板支撑及型钢拱肋顶部浇筑有一层混凝土拱肋,混凝土拱肋顶部浇筑有混凝土填充层,混凝土填充层顶面与隧道底面齐平。施工时首先通过竖转施工完成型钢拱肋安装,然后利用型钢拱肋作为支架施工上部混凝土拱肋,充分利用型钢拱肋自重小、强度高、安装方便快捷的特点,避免桥下搭设模板支架,从而降低施工难度,保障了施工质量,降低安全风险,减少施工成本。(The invention provides a steel-concrete combined arch bridge crossing a karst cave in a tunnel and a construction method thereof. During construction, firstly, the section steel arch rib is installed through vertical rotation construction, then the section steel arch rib is used as a concrete arch rib at the upper part of the support construction, the characteristics of small self weight, high strength and convenience and quickness in installation of the section steel arch rib are fully utilized, and a template support is prevented from being erected under a bridge, so that the construction difficulty is reduced, the construction quality is guaranteed, the safety risk is reduced, and the construction cost is reduced.)

1. The utility model provides a reinforced concrete combination arch bridge of karst cave is striden in tunnel which characterized in that: including many shaped steel arch ribs that set up side by side, the both ends of every shaped steel arch rib with pour the hunch seat fixed connection on the wall of solution cavity both sides, have a determining deviation between adjacent shaped steel arch rib to connect through many crossbeams, the crossbeam upper berth is equipped with supporting steel plate, and steel sheet support and shaped steel arch rib top have been pour one deck concrete arch rib, and concrete filling layer has been pour at concrete arch rib top, and concrete filling layer top surface flushes with the tunnel bottom surface.

2. The reinforced concrete composite arch bridge spanning a karst cave in a tunnel according to claim 1, wherein: the structural steel arch rib is formed by bending I-shaped steel, two connecting plates are symmetrically welded on two sides of a web plate of the I-shaped steel at intervals, and two ends of each cross beam are respectively connected with the two connecting plates which are opposite to the two adjacent arch ribs through bolts.

3. A construction method of a reinforced concrete combined arch bridge spanning a karst cave in a tunnel is characterized by comprising the following steps:

(1) two opposite arch bases are poured on two side walls of the karst cave, a hinged support is preset on one arch base, and a section steel arch rib embedded section is arranged on the other arch base;

(2) bending a plurality of I-shaped steels into arc-shaped arch ribs, wherein the span of the arch ribs is arranged according to the distance between two arch seats; connecting 2-3 arch ribs into a group by adopting a cross beam;

(3) hoisting a group of arch ribs above an arch center provided with a hinged support by using a truck crane, and connecting one end of each arch rib with the arch center through a rotary hinge;

(4) a fixed pulley is arranged at a certain height of the side wall of the karst cave above the arch seat, and a buckle cable is connected with the other end of the arch rib after passing around the fixed pulley;

(5) slowly releasing the buckle cable to enable the arch rib to rotate towards the arch base on the other side of the karst cave under the action of gravity;

(6) after the arch rib is vertically rotated to the right position, the arch rib is fixed with the hinged end of the arch base, and the other end of the arch rib is welded with the arch rib embedded section on the other arch base;

(7) sequentially mounting and fixing the groups of arch ribs on the arch seats according to the method, connecting the groups of arch ribs into a whole by using the cross beam, and welding a pattern steel plate on the upper part of the cross beam;

(8) the profile steel arch rib and a steel plate welded on the cross beam are used as template supports, and a layer of concrete arch rib is poured on the profile steel arch rib;

(9) and after the concrete arch rib reaches the design strength, pouring a concrete filling layer at the top of the concrete arch rib until the concrete arch rib is flush with the bottom surface of the tunnel in height.

Technical Field

The invention belongs to the technical field of tunnel construction, and relates to a steel-concrete combined arch bridge structure and a construction method thereof, which are adopted for crossing a karst cave when the karst cave is encountered in the tunnel excavation process.

Background

When meeting the solution cavity in the tunnel excavation construction process, for the less solution cavity, generally adopt the backfill mode to handle, for bigger solution cavity, can adopt the bridge to stride across. However, for large and deep karst caves, large machinery is difficult to play a role due to the narrow field in the tunnel, and the construction efficiency of the bridge in the cave is low; particularly, for the overflow karst cave, the problems of difficult erection of template supports under the bridge and the like exist, and the difficulty of constructing the bridge in the karst cave is high.

Disclosure of Invention

The invention aims to provide a reinforced concrete combined arch bridge structure crossing a large karst cave in a tunnel and a construction method aiming at the problem of high difficulty in crossing the large karst cave in the tunnel construction process, so that the construction difficulty is reduced, and the construction efficiency is improved.

The invention provides a reinforced concrete combined arch bridge crossing a karst cave in a tunnel, which is characterized in that: including many shaped steel arch ribs that set up side by side, the both ends of every shaped steel arch rib with pour the hunch seat fixed connection on the wall of solution cavity both sides, have a determining deviation between adjacent shaped steel arch rib to connect through many crossbeams, the crossbeam upper berth is equipped with supporting steel plate, and steel sheet support and shaped steel arch rib top have been pour one deck concrete arch rib, and concrete filling layer has been pour at concrete arch rib top, and concrete filling layer top surface flushes with the tunnel bottom surface.

The invention provides a construction method of a reinforced concrete combined arch bridge spanning a karst cave in a tunnel, which is characterized by comprising the following steps of:

(1) two opposite arch bases are poured on two side walls of the karst cave, a hinged support is preset on one arch base, and a section steel arch rib embedded section is arranged on the other arch base;

(2) bending a plurality of I-shaped steels into arc-shaped arch ribs, wherein the span of the arch ribs is arranged according to the distance between two arch seats; connecting 2-3 arch ribs into a group by adopting a cross beam;

(3) hoisting a group of arch ribs above an arch center provided with a hinged support by using a truck crane, and connecting one end of each arch rib with the arch center through a rotary hinge;

(4) a fixed pulley is arranged at a certain height of the side wall of the karst cave above the arch seat, and a buckle cable is connected with the other end of the arch rib after passing around the fixed pulley;

(5) slowly releasing the buckle cable to enable the arch rib to rotate towards the arch base on the other side of the karst cave under the action of gravity;

(6) after the arch rib is vertically rotated to the right position, the arch rib is fixed with the hinged end of the arch base, and the other end of the arch rib is welded with the arch rib embedded section on the other arch base;

(7) sequentially mounting and fixing the groups of arch ribs on the arch seats according to the method, connecting the groups of arch ribs into a whole by using the cross beam, and welding a pattern steel plate on the upper part of the cross beam;

(8) the profile steel arch rib and a steel plate welded on the cross beam are used as template supports, and a layer of concrete arch rib is poured on the profile steel arch rib;

(9) and after the concrete arch rib reaches the design strength, pouring a concrete filling layer at the top of the concrete arch rib until the concrete arch rib is flush with the bottom surface of the tunnel in height.

According to the invention, the section steel is adopted as the arch rib to cross the karst cave according to the topographic conditions and the bridge span structure characteristics at the karst cave, the section steel arch rib is firstly assembled in groups through a vertical rotation construction process during construction, the difficulty that large mechanical equipment in a tunnel is difficult to deploy is solved, then the section steel arch rib is used as a support to construct an upper concrete arch rib, the section steel arch rib and the concrete arch rib form a steel-concrete combined arch structure to jointly bear upper load after construction is completed, the characteristics of small self weight, high strength, convenient and quick installation and the like of the section steel arch rib are fully utilized, and the template support is prevented from being erected under the bridge, so that the construction difficulty is reduced, the construction quality is ensured, the safety risk is reduced, and.

Drawings

FIG. 1 is a schematic side view of a steel-concrete composite arch of the present invention;

FIG. 2 is a schematic structural view of the steel-concrete composite arch in elevation;

FIG. 3 is an enlarged view of a portion of FIG. 2;

FIG. 4 is a schematic plan view of a steel section rib;

FIG. 5 is a schematic view of the state of hoisting a section steel arch rib by using a truck crane;

FIG. 6 is a schematic view showing the vertical rotation of the steel arch rib;

FIG. 7 is a schematic view of the installation of the section steel ribs across the karst cave.

Detailed Description

As shown in fig. 1, 2, 3 and 4, the reinforced concrete combined arch bridge crossing a karst cave in a tunnel provided by the invention comprises a plurality of profile steel arch ribs 1 arranged in parallel, two ends of each profile steel arch rib 1 are fixedly connected with arch bases 3 poured on two side walls of the karst cave 2, a certain distance is reserved between the adjacent profile steel arch ribs and connected through a plurality of cross beams 4, supporting steel plates 5 are paved on the cross beams 4, a layer of concrete arch rib 6 is poured on the top of each supporting steel plate 5 and the top of each profile steel arch rib, a concrete filling layer 7 is poured on the top of each concrete arch rib 6, and the top surfaces of the concrete filling layers 7 are flush with the bottom surfaces of the tunnels 8.

When the invention is implemented specifically, the section steel arch rib 1 can be formed by bending I-steel, two connecting plates 9 are symmetrically welded on two sides of a web plate of the I-steel at certain intervals, and two ends of each cross beam 4 are respectively connected with the two connecting plates 9 which are opposite to the two adjacent arch ribs through bolts.

The concrete-reinforced composite arch bridge spanning the karst cave in the tunnel has the following specific construction method:

(1) as shown in fig. 5, two opposite arch bases 3 are poured on two side walls of the karst cave 2, wherein a hinged support 31 is preset on one arch base, and a section steel arch rib embedded section 32 is arranged on the other arch base;

(2) bending a plurality of I-shaped steels into an arc-shaped arch rib 1, wherein the span of the arch rib is arranged according to the distance between two arch seats; connecting 2-3 arch ribs into a group by adopting a cross beam;

(3) hoisting a group of arch ribs above an arch base 3 provided with a hinged support by using a truck crane 10, and connecting one end of each arch rib 1 with the arch base 3 through a rotary hinge;

(4) as shown in fig. 6, a fixed pulley 11 is arranged at a certain height of the side wall of the karst cave above an arch seat hinged with the arch rib, and a buckle cable 12 is connected with the other end of the arch rib 1 after passing around the fixed pulley;

(5) slowly releasing the buckle cable 12 to enable the arch rib to rotate towards the arch base on the other side of the karst cave under the action of gravity;

(6) as shown in fig. 7, after the arch rib is vertically rotated to the right position, the arch rib and the hinged support of the arch base are fixedly sealed, and the other end of the arch rib 1 is welded with an arch rib embedded section 32 on the other arch base 3;

(7) sequentially mounting and fixing the groups of arch ribs on the arch seats according to the method, connecting the groups of arch ribs into a whole by using the cross beam, and welding a support steel plate on the upper part of the cross beam;

(8) the profile steel arch rib and the supporting steel plate welded on the cross beam are used as template supports, and a layer of concrete arch rib is poured on the profile steel arch rib;

(9) and after the concrete arch rib reaches the design strength, pouring a concrete filling layer at the top of the concrete arch rib until the concrete filling layer is flush with the bottom surface of the tunnel, and then performing upper tunnel structure construction.