Construction rescue and traffic congestion evacuation system and construction method for super-long highway tunnel group

Abstract

The application discloses a super-long highway tunnel group construction rescue and traffic congestion dispersing system and a construction method, belongs to the technical field of bridge and tunnel engineering, and comprises a left-line bridge, a right-line bridge, a rescue dispersing platform, a plurality of super-long tunnels, a tunnel vehicle horizontal hole, a tunnel fire rescue chamber, a tunnel construction inclined shaft, a permanent and temporary combined construction access and a local provincial road. The left-line bridge and the right-line bridge are used for crossing a V-shaped valley and connecting two super-long separated tunnels on the two sides of the valley. The rescue dispersing platform is composed of a plurality of bridges arranged transversely and side by side. The bridges are independent of each other and are connected through longitudinal bridge deck expansion joints. The technical scheme is used to solve the problems that, due to the influence of various objective factors such as the vertical and steep mountains in the hinterland of the Qinling Mountains, national nature reserves and water protection areas, there is a lack of suitable large-area flat ground for arranging highway tunnel rescue stations, and super-long highway tunnel groups are difficult to arrange construction rescue, traffic dispersing, temporary parking on long longitudinal slope sections and heavy vehicle cooling sites.

Description

Technical Field

[0001] This invention belongs to the field of bridge and tunnel engineering technology, specifically relating to a construction rescue and traffic congestion evacuation system and construction method for ultra-long highway tunnel groups. Background Technology

[0002] The Qinling Tiantaishan Tunnel is a key control project of the Baoji-Pingkan section of the Yinchuan-Kunming National Expressway (G85) in Shaanxi Province. With a total length of 32km, a tunnel ratio of 98.1%, and an average longitudinal slope of 1.83%, it forms the Qinling Tiantaishan Ultra-Long Highway Tunnel Group. This group includes two extra-long tunnels, five long tunnels, and three medium-sized tunnels. The Qinling Tiantaishan Tunnel is located in the middle to later section of the tunnel group, with a single-tube length of 15.56km and a single-tube excavation cross-section of 160m. 2 It is currently the world's longest six-lane, two-way highway tunnel and also the largest highway tunnel in terms of construction scale. The Qinling Tiantaishan Tunnel and its 32km network of highway tunnels, as a world-renowned mega-project, possess several significant engineering characteristics: "ultra-long, multi-lane, deep burial, long longitudinal slope, high bridge-to-tunnel ratio, and ecological sensitivity."

[0003] Extra-long, multi-lane: The Qinling Tiantaishan Tunnel is 15.56km long, adopts a two-way six-lane technical standard, has a maximum excavation span of 16.55m, and an excavation area of ​​approximately 160m². 2 It is currently the world's largest in terms of construction scale;

[0004] The Qinling Mountains are extremely complex in terms of engineering and hydrogeology. The maximum burial depth of the Qinling Tiantaishan Tunnel is 973m, and it crosses 19 faults. The risks of engineering disasters such as rock bursts and sudden water inrush are prominent.

[0005] Long longitudinal slope and high bridge-to-tunnel ratio: The Qinling Tiantaishan Tunnel and the 32km highway tunnel group it is located in have a bridge-to-tunnel ratio as high as 98.1% and an average longitudinal slope of 1.83%, making it an ultra-long-distance continuous longitudinal slope tunnel group.

[0006] Ecologically sensitive: The Qinling Tiantaishan Tunnel Group passes under the source of the Jialing River and is adjacent to important ecologically sensitive areas such as the Tiantaishan National Scenic Area and the Shaanxi Shenshahe Provincial Nature Reserve. The total amount of waste material from the tunnels reaches 5.17 million cubic meters, and the requirements for environmental protection and soil and water conservation are high. The ecological red line of the Qinling Mountains must be strictly adhered to.

[0007] In summary, the Qinling Tiantaishan ultra-long highway tunnel group is characterized by its exceptionally long tunnels, continuous long downhill slopes, and ecologically sensitive areas. This presents significant challenges in construction organization, operational safety risks, and disaster prevention and rescue requirements. In particular, the northern entrance of the Qinling Tiantaishan Tunnel (an exceptionally long tunnel, 15.56 km long) is adjacent to the southern entrance of the Qingshiling Tunnel (an exceptionally long tunnel, 3.6 km long), crossing the "V-shaped" Shensha River Valley. The tunnel entrance is approximately 70 meters above the valley floor, and the Shensha River is a core area of ​​a provincial nature reserve and a tributary of the Jia-Qing drinking water source. Therefore, the latter part of the Qinling Tiantaishan ultra-long tunnel group lacks suitable large-area flat terrain for setting up highway tunnel rescue stations, and the northern entrance of the Qinling Tiantaishan Tunnel lacks suitable areas for construction rescue, traffic evacuation, temporary parking on long longitudinal slopes, and cooling of heavy vehicles. Summary of the Invention

[0008] In view of this, the purpose of this invention is to provide a construction rescue and traffic congestion evacuation system and method for ultra-long highway tunnel groups, to solve the problems caused by various objective factors such as the steep terrain of the Qinling Mountains, national nature reserves, and water source protection areas, which result in a lack of suitable large-area flat land for setting up highway tunnel rescue stations, and the difficulty in setting up construction rescue, traffic evacuation, temporary parking on long longitudinal slopes, and heavy vehicle cooling areas in ultra-long highway tunnel groups. To achieve the above objectives, this invention provides the following technical solution:

[0009] This invention relates to a construction rescue and traffic congestion evacuation system for ultra-long highway tunnel complexes, comprising a left-line bridge, a right-line bridge, a rescue and evacuation platform, multiple extra-long tunnels, tunnel vehicular cross passages, tunnel construction inclined shafts, temporary and permanent access roads, and local provincial highways. The left-line and right-line bridges are used to cross a "V-shaped" canyon and connect two extra-long tunnels on either side of the canyon. The rescue and evacuation platform consists of multiple bridges arranged horizontally side-by-side, each independent of the others, connected laterally by longitudinal bridge deck expansion joints. The rescue and evacuation platform is located on the left-line and right-line bridges. Between the bridge and the line, both of the two extra-long tunnels on either side of the "V-shaped" canyon are equipped with tunnel vehicular cross passages and tunnel construction inclined shafts. One end of the tunnel construction inclined shaft is connected to the extra-long tunnel, and the other end is connected to a temporary construction access road. The temporary construction access road is used to connect the tunnel construction inclined shaft to the local provincial highway. Both of the extra-long tunnels on either side of the V-shaped canyon are equipped with tunnel vehicular cross passages, which are used to connect the left tunnel and the right tunnel. The positions of the tunnel vehicular cross passages and the tunnel construction inclined shaft openings correspond to each other.

[0010] Furthermore, the rescue and evacuation platform is laterally spliced ​​to the left and right bridges on both sides and connected by longitudinal bridge deck expansion joints. Guardrails are provided on the edges of the lateral splices of the left and right bridges. The guardrails include reinforced concrete guardrails and open movable guardrails. A gap is provided in the middle of the reinforced concrete guardrails of the left and right bridges, and the open movable guardrails are set in the gaps.

[0011] Furthermore, the left-line bridge, the right-line bridge, and several bridges of the rescue and evacuation platform are all continuous rigid frame bridges.

[0012] Furthermore, the left-line bridge, right-line bridge, and multiple continuous rigid frame bridges of the rescue and evacuation platform are arranged along the mountainside on both sides of the "V-shaped" canyon. The bridge lengths and spans of multiple bridges are not exactly the same, including symmetrical continuous rigid frame bridges with side spans and asymmetrical continuous rigid frame bridges with side spans.

[0013] Furthermore, the rescue and evacuation platform has a tunnel fire rescue chamber located at one end of the bridge in the middle position.

[0014] This invention also includes a construction method for a continuous rigid frame bridge with asymmetrical side spans and an extremely small side-to-middle span ratio. The middle span on the side with the smaller chainage has one more beam segment than the side span on the side with the smaller chainage, and the side-to-middle span ratio is only 0.513. The largest symmetrical cantilever on the side with the smaller chainage is the n-1 segment of the box girder, and the largest symmetrical cantilever on the side with the larger chainage is the nth segment of the box girder. The key construction steps of the bridge are as follows:

[0015] (1) After the construction of the pile foundation, pile cap, bridge pier and box girder No. 0 segment is completed, install the hanging basket and repeat the symmetrical cantilever process until the box girder No. n-1 segment is cantilevered, that is, the largest symmetrical cantilever on the small pile side; after the abutment construction is completed, erect the support and pre-stress it next to the abutment of the side span, and pour the side span cast-in-place segment on the support.

[0016] (2) Add counterweights simultaneously to beam segment n-1 on the side span of the small pile number and beam segment n-1 on the middle span of the small pile number. The weight of the counterweights is the weight of the closure segment of the side span of the small pile number.

[0017] (3) When the daily temperature change is minimal, lock the closure section of the side span of the small pile number, weld the stiff frame, pour the concrete of the closure section of the side span of the small pile number, unload the counterweight of the n-1 beam section of the side span of the small pile number, and then dismantle the support of the cast-in-place section of the side span of the small pile number.

[0018] (4) Apply permanent concrete counterweight to the bottom plate inside the box girder of the n-1 and n-2 beam segments on the side span of the small pile number, and increase the counterweight weight of the n-1 beam segment in the middle span of the small pile number. The counterweight weight is increased from the weight of the closure section of the side span of the small pile number to the weight of the n beam segment.

[0019] (5) Cast the nth beam segment of the middle span on the side of the small pile number, and unload the counterweight of the n-1th beam segment of the middle span on the side of the small pile number at the same time, and cast the nth beam segment of the middle span on the side of the large pile number and the nth beam segment of the side span on the side of the large pile number at the same time.

[0020] (6) Remove the hanging basket, install the closure frame, and when the daily temperature change is minimal, lock the closure section of the middle span and the side span of the large pile number, weld the rigid frame, pour the concrete of the closure section of the middle span and the side span of the large pile number, and then remove the support of the cast-in-place section of the side span of the large pile number.

[0021] (7) After the bridge closure is completed, the closure section hangers are removed, the bridge deck system construction is completed, and the bridge ancillary facilities are installed.

[0022] The present invention also includes a construction organization scheme for the abutments of multiple continuous rigid frame bridges that make up the rescue and evacuation platform. The specific steps are as follows: (1) From the local provincial highway, the bridge site is reached through the temporary construction access road, and then the main tunnels of the left tunnel and the right tunnel are entered through the tunnel construction inclined shaft and the tunnel vehicle cross passage.

[0023] (2) Excavate from the main tunnels of the left and right tunnels toward the "V" shaped canyon and exit in the opposite direction;

[0024] (3) Excavate a construction access road in the shape of a "tiger's mouth" to minimize damage to the original mountain;

[0025] (4) After the construction access road is completed, the bridge abutment construction operation chamber is excavated in the opposite direction of the "V-shaped" canyon, which is similar to a "glasses-shaped" arch tunnel.

[0026] (5) Constructing bridge abutments in the bridge abutment construction operation chamber;

[0027] (6) After the bridge abutment is completed, the mountain is broken layer by layer from top to bottom, and the bridge abutment construction operation chamber is demolished.

[0028] This invention also includes a construction method for high-pile foundations located adjacent to a river and backed by a mountain, the specific steps of which are as follows:

[0029] (1) Clear the original mountain surface, construct a superimposed inclined road shoulder retaining wall along the river, and excavate steps on the mountain behind the retaining wall to minimize damage to the original mountain.

[0030] (2) Construct anchor bolts and grout, pre-embed steel casing for bridge pile foundation, fill the original mountain with rubble concrete, and construct a bridge pile foundation construction platform;

[0031] (3) Construct bridge pile foundations and high pile caps.

[0032] The beneficial effects of this invention are as follows:

[0033] (1) This invention constructs a construction rescue and traffic congestion evacuation system for ultra-long highway tunnel groups, which solves the problem of lacking suitable large-area flat land for setting up highway tunnel rescue stations due to various objective factors such as the steep mountains in the hinterland of the Qinling Mountains, national nature reserves and water source protection areas. It provides space and convenience for construction rescue, traffic evacuation, temporary parking on long longitudinal slopes and cooling of heavy vehicles in ultra-long highway tunnel groups.

[0034] (2) The present invention provides a construction method for a continuous rigid frame bridge with asymmetric side spans and a very small side-to-middle span ratio, which makes it possible to build the bridge according to the direction of the vertical steep mountain and minimizes the damage to the original mountain.

[0035] (3) This invention provides a bridge abutment construction organization scheme where there is no roadbed or tunnel to pass through on the front and rear sides of the bridge. It establishes a construction organization mode of reverse tunnel exit, construction of "tiger mouth" access road, and excavation of "spectacle-shaped" bridge abutment construction operation chamber. It solves the problem of bridge abutment construction organization of multiple continuous rigid frame bridges that form a rescue and evacuation platform. At the same time, it effectively prevents workers from being injured by falling rocks while minimizing damage to the original mountain, thus maximizing the protection of workers' life and health.

[0036] (4) This invention provides a method for constructing bridge piers that are close to the river and backed by the mountain. It adopts a variety of design measures such as river retaining walls, high pile caps and retaining wall superposition, which ensures that the construction of bridge piers that are close to the river and backed by the mountain is achieved with minimal damage to the mountain slope. At the same time, it effectively solves the problem of large rocks flying into the bridge piers in the "V" shaped valley with a large gradient, as well as the problem of pile foundation protection under the scouring of debris flow or strong water flow.

[0037] (5) The ultra-long highway tunnel group construction rescue and traffic congestion evacuation system of this invention connects two extra-long separated tunnels on both sides of the "V-shaped" canyon from the outside through the left-line bridge, the rescue and evacuation platform and the right-line bridge. When a disaster or accident occurs in one side of the tunnel, the trapped personnel and vehicles can be quickly diverted to the opposite tunnel through the rescue and evacuation platform, and then the trapped personnel and vehicles can be evacuated to the local provincial highway through the tunnel vehicle cross passage, the tunnel construction inclined shaft and the permanent and temporary construction access road. At the same time, the rescue vehicles on the rescue and evacuation platform can quickly reach the disaster or accident site, realizing the emergency rescue and one-way traffic maintenance functions of the ultra-long highway tunnel group.

[0038] Other advantages, objectives, and features of the invention will be set forth in the following description and will be apparent to those skilled in the art in some respects, or may be learned by practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0039] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the following figures are provided for illustration:

[0040] Figure 1 This is a schematic diagram of the construction rescue and traffic congestion evacuation system for ultra-long highway tunnel groups according to the present invention;

[0041] Figure 2This is a schematic diagram of the elevation and cross-section of the three-span continuous rigid frame bridge that forms the rescue and evacuation platform of the present invention.

[0042] Figures 3-9 This is a schematic diagram of the construction method for the continuous rigid frame bridge with asymmetrical side spans and minimal side-to-mid span ratio according to the present invention.

[0043] Figure 10 This is a schematic diagram of the construction organization scheme for bridge abutments in which there is no roadbed or tunnel to which the bridge can be used for passage.

[0044] Figure 11 This is a schematic diagram illustrating the emergency rescue and one-way traffic maintenance functions of an ultra-long highway tunnel group using a rescue and evacuation platform in this invention.

[0045] Figure 12 This is a schematic diagram of the high-pile foundation that is adjacent to the river and backed by the mountain in this invention. Detailed Implementation

[0046] like Figure 1-2 As shown, the present invention relates to an ultra-long highway tunnel group construction rescue and traffic congestion evacuation system, including a left-line bridge, a right-line bridge, a rescue and evacuation platform, multiple extra-long tunnels, tunnel vehicular cross passages, tunnel fire rescue chambers (personnel duty locations), tunnel construction inclined shafts, temporary and permanent construction access roads, and local provincial highways. The left-line and right-line bridges are used to cross a "V-shaped" canyon and connect two extra-long separated tunnels on either side of the canyon. The rescue and evacuation platform consists of multiple bridges arranged horizontally side-by-side, each independent of the others, connected laterally by longitudinal bridge deck expansion joints. The platform is located between the left and right bridges. Both of the extra-long tunnels on both sides of the "V-shaped" canyon are equipped with tunnel vehicular cross passages and tunnel construction inclined shafts. One end of the tunnel construction inclined shaft is connected to the extra-long tunnel, and the other end is connected to the temporary construction access road. The temporary construction access road is used to connect the tunnel construction inclined shaft to the local provincial highway. Both of the extra-long tunnels on both sides of the V-shaped canyon are equipped with tunnel vehicular cross passages, which are used to connect the left and right tunnels. The positions of the tunnel vehicular cross passages and the tunnel construction inclined shaft openings are corresponding.

[0047] Preferably, the left-line bridge, the right-line bridge, and several bridges of the rescue and evacuation platform are all continuous rigid frame bridges. In this specific embodiment, the several bridges that make up the rescue and evacuation platform are composed of the middle bridge No. 1, the middle bridge No. 2, and the middle bridge No. 3. Of course, the specific number of bridges can be selected and designed according to the actual situation. Each bridge is independent of each other and is connected laterally through longitudinal expansion joints. No guardrails are installed on the rescue and evacuation platform.

[0048] Preferably, the rescue and evacuation platform is laterally spliced ​​to the left and right bridges on both sides, connected by longitudinal bridge deck expansion joints. Guardrails are installed at the edges of the lateral splices on the left and right bridges. These guardrails include reinforced concrete guardrails and open movable guardrails. A notch is provided in the middle of the reinforced concrete guardrails on both the left and right bridges, and the open movable guardrail is placed within the notch. The left and right bridges serve normal driving functions, while the rescue and evacuation platform serves as a construction rescue, traffic evacuation, and temporary parking and cooling platform for heavy vehicles on long slope sections of the ultra-long highway tunnel complex.

[0049] Preferably, the left-line bridge, the right-line bridge, and the multiple continuous rigid frame bridges of the rescue and evacuation platform are arranged along the mountain direction on both sides of the "V-shaped" canyon. The bridge lengths and spans of the multiple bridges are not exactly the same, including symmetrical continuous rigid frame bridges with side spans and asymmetrical continuous rigid frame bridges with side spans.

[0050] Preferably, the rescue and evacuation platform has a tunnel fire rescue chamber at one end of the bridge in the middle position.

[0051] The following is an engineering example of a construction rescue and traffic congestion evacuation system for ultra-long highway tunnel groups designed according to the above technical solution:

[0052] The Qinling Tiantaishan Tunnel is a key control project of the Baoji-Pingkan section of the Yinchuan-Kunming National Expressway (G85) in Shaanxi Province. With a total length of 32km, a tunnel ratio of 98.1%, and an average longitudinal slope of 1.83%, it forms the Qinling Tiantaishan Ultra-Long Highway Tunnel Group. This group includes two extra-long tunnels, five long tunnels, and three medium-sized tunnels. The Qinling Tiantaishan Tunnel is located in the middle to later section of the tunnel group, with a single-tube length of 15.56km and a single-tube excavation cross-section of 160m. 2 The Qinling Tiantaishan Tunnel is currently the world's longest six-lane, two-way highway tunnel and also the largest highway tunnel in terms of construction scale. As a world-renowned mega-project, the Qinling Tiantaishan Tunnel and its 32km network of highway tunnels are characterized by several significant engineering features, including "ultra-long length, multiple lanes, deep burial, long longitudinal slope, high bridge-to-tunnel ratio, and ecological sensitivity." It features an exceptionally long tunnel, continuous long downhill slopes, and an ecologically sensitive area, making its construction organization extremely difficult, its operational safety risks high, and its disaster prevention and rescue requirements stringent. In particular, the northern entrance of the Qinling Tiantaishan Tunnel (an exceptionally long tunnel, 15.56km in length) is adjacent to the southern entrance of the Qingshiling Tunnel (an exceptionally long tunnel, 3.6km in length), crossing the "V-shaped" Shensha River Valley. The tunnel entrance is approximately 70m above the valley floor, and the Shensha River is a core tributary of a provincial nature reserve and a drinking water source for the Jia-Qing region. Therefore, the middle and later sections of the Qinling Tiantaishan ultra-long tunnel group lack suitable large-area flat land for setting up highway tunnel rescue stations, and the north entrance of the Qinling Tiantaishan tunnel lacks suitable construction rescue, traffic evacuation, temporary parking on long longitudinal slopes, and heavy vehicle cooling areas.

[0053] Considering the current construction status, construction period, project cost, and other factors of the Baoping Expressway, and taking into account the topography of the Shensha River Valley and existing buildings, the following design scheme is proposed:

[0054] Design Scheme 1 (High Embankment): The advantage of this scheme is that it can maximize the use of tunnel spoil from the Qinling Tiantaishan Tunnel and Qingshiling Tunnel. The disadvantage is that the high embankment area contains several important ecologically sensitive areas, including the Tiantaishan National Scenic Area, the Jiaqing drinking water source, and the provincial-level Shensha River Nature Reserve. Furthermore, there is a stone arch bridge of the Baoji-Chengdu Railway at the mouth of the Shensha River valley; if the tunnel spoil filling fails, it will damage the stone arch bridge. Therefore, from the perspective of maintaining railway safety and protecting the environment, the high embankment scheme is unsuitable.

[0055] Design Scheme 2 (Single-T Rigid Frame Bridge): The advantage of this scheme is that it eliminates the need to build bridge piers on both sides of the "V-shaped" Shensha River Valley, thus avoiding damage to the slopes of the Qinling Tiantai Mountain and Qingshiling Mountains. The disadvantage is that the piers of the single-T rigid frame bridge are inevitably located in the riverbed. However, the Shensha River is narrow and deep with a significant gradient. There are two large landslides upstream, and many large rocks (3-6 meters) exist in the riverbed. During the rainy season, there is a possibility of forming a barrier lake, which could then lead to mudslides or large flying rocks impacting the bridge piers. Therefore, from the perspective of ensuring the safety of bridge construction and operation, a single-T rigid frame bridge is unsuitable.

[0056] Design Scheme 3 (Three-span continuous rigid frame bridge): The advantages of this scheme are lower construction costs compared to the single-T rigid frame bridge scheme and avoidance of setting up bridge piers in the riverbed; the disadvantage is that it may cause small-scale damage to the slope toe of the Qinling Tiantaishan and Qingshiling mountains. Regarding the problem of tunnel spoil removal for the two extra-long tunnels, the design adopted a solution of constructing temporary and permanent construction access roads and tunnel construction inclined shafts to connect the main tunnel of the extra-long tunnel with Provincial Highway 219, so as to transport the tunnel spoil away in a timely manner. This solution was then widely applied to various aspects of the roadbed filling and protection project of the Qinling Tiantaishan service area on the Baoping Expressway. For the two large landslides upstream of the Shensha River and the presence of large rocks in the riverbed, the design adopted a solution of setting up riverside retaining walls and overlapping retaining walls to avoid debris flows and large flying rocks impacting the bridge piers during the rainy season. Meanwhile, the Shensha River Bridge (left-line bridge, right-line bridge and rescue and evacuation platform), multiple extra-long tunnels, tunnel vehicular cross passages, tunnel fire rescue chambers, temporary and permanent construction access roads, tunnel construction inclined shafts and Provincial Highway 219 will form a complete construction rescue and traffic congestion evacuation system for an ultra-long highway tunnel group.

[0057] Based on the above considerations, the rescue and evacuation platform is designed using design scheme 3 (a three-span continuous rigid frame bridge).

[0058] The Shenshahe Bridge is located in the center of the Qinling Tiantaishan ultra-long highway tunnel group. With a width of 77 meters, it is currently the widest prestressed concrete continuous rigid frame bridge in China. The bridge consists of five continuous rigid frame bridges arranged side-by-side: the left-line Shenshahe Bridge, the middle bridges (No. 1, No. 2, and No. 3), and the right-line Shenshahe Bridge. Each bridge is independent and its span follows the mountain's contours. They are connected laterally via longitudinal bridge deck expansion joints, a first in China. The left and right-line Shenshahe Bridges connect to the Qingshiling Tunnel on the lower pile side and the Qinling Tiantaishan Tunnel on the higher pile side, both being bridge-to-tunnel connections. The left and right-line Shenshahe Bridges are 16 meters wide, while the middle bridges (No. 1, No. 2, and No. 3) are 15 meters wide. A fire rescue tunnel is designed on the lower pile side of the middle bridge (No. 2). The bridge span combination is as follows:

[0059] Left-line Shensha River Bridge: 47+76+47=170m;

[0060] Middle Bridge No. 1: 39 + 76 + 43 = 158m;

[0061] Bridge No. 2 in the middle: 48 + 80 + 48 = 176m;

[0062] Bridge No. 3 in the middle: 47 + 80 + 49 = 176m;

[0063] Right-line Shensha River Bridge: 48+80+48=176m.

[0064] The left and right Shenshahe Bridges serve normal traffic functions, while the middle bridges No. 1, No. 2, and No. 3 serve as traffic construction and rescue, traffic congestion relief, and temporary parking and cooling platforms for heavy vehicles on long slopes in the super-long highway tunnel group before and after the sections.

[0065] Because the Shensha River Bridge follows the orientation of the mountains on both sides of the "V-shaped" canyon in terms of its bridge length and span, the five continuous rigid frame bridges do not have the same length and main span. They include continuous rigid frame bridges with symmetrical side spans and continuous rigid frame bridges with asymmetrical side spans. The most representative of these is Bridge No. 1 in the middle, which is a continuous rigid frame bridge with asymmetrical side spans and a very small side-to-middle span ratio, with a side-to-middle span ratio of only 0.513.

[0066] The span combination of the No. 1 bridge in the middle is (39+76+43)m, and the beam segments of the side spans and the middle span are divided as follows:

[0067] (1) Side spans with small pile numbers: Section 0 (4.5m in length), cantilever casting section (sections 1-5, 3m in length, sections 6-9, 3.5m in length), closure section (2m in length) and side span cast-in-place section (3.34m in length).

[0068] (2) Half of the middle span: Section 0 (4.5m in length), cantilever casting section (sections 1-5, 3m in length, sections 6-10, 3.5m in length), and closure section (1m in length).

[0069] (3) Side spans of large chainages: Section 0 (4.5m in length), cantilevered casting section (sections 1-5, 3m in length, sections 6-10, 3.5m in length), closure section (2m in length) and side span cast-in-place section (3.84m in length).

[0070] As can be seen from the beam segment division, the side span of the small pile number is one beam segment 10 less than half of the middle span. During construction, it is impossible to carry out the conventional cantilever symmetrical casting, which brings certain difficulties to the design.

[0071] To solve this problem, such as Figure 3-9 As shown, the present invention also includes a construction method for a continuous rigid frame bridge with asymmetrical side spans and a minimal side-to-mid span ratio. Based on an engineering example, the key construction steps of the bridge are as follows:

[0072] (1) After the construction of the pile foundation, pile cap, bridge pier and box girder No. 0 beam segment is completed, install the hanging basket and repeat the symmetrical cantilever process until the cantilever is poured to box girder No. 9 beam segment, that is, the first span maximum symmetrical cantilever; after the construction of No. 0 bridge abutment is completed, erect a support next to No. 0 bridge abutment and pre-press it, and pour the small pile side span cast-in-place segment on the support.

[0073] (2) Counterweights were simultaneously added to beam segment 9 on both the side span and the middle span of beam segment 9 on the side of the lower pile number. The counterweight weight was 81.1 kg.

[0074] The total weight is 81.1 tons, of which 81.1 tons are the weight of the side span closure section at the smaller pile number.

[0075] (3) When the daily temperature change is minimal, lock the closure section of the side span of the small pile number, weld the stiff frame, pour the concrete of the closure section of the side span of the small pile number, unload the counterweight of the No. 9 beam section of the side span of the small pile number simultaneously, and then dismantle the support of the cast-in-place section of the side span of the small pile number.

[0076] (4) Apply permanent concrete counterweight to the bottom plate inside the box girder of the No. 8 and No. 9 beam segments on the side span of the small pile number, and increase the counterweight of the No. 9 beam segment in the middle span of the small pile number. The counterweight increases from 81.1 tons to 109.3 tons, of which 109.3 tons is the weight of the No. 10 beam segment.

[0077] (5) Suspend the casting of beam segment 10 on the side of the small pile number, unload the counterweight of beam segment 9 on the side of the small pile number, and simultaneously suspend the casting of beam segment 10 on the side of the large pile number and beam segment 10 on the side of the large pile number.

[0078] (6) Remove the hanging basket, install the closure frame, and when the daily temperature change is minimal, lock the closure section of the middle span and the side span of the large pile number, weld the rigid frame, pour the concrete of the closure section of the middle span and the side span of the large pile number, and then remove the support of the cast-in-place section of the side span of the large pile number.

[0079] (7) After the bridge closure is completed, the closure section hangers are removed, the bridge deck system construction is completed, and the bridge ancillary facilities are installed.

[0080] Considering that the two sides of the middle bridges No. 1, No. 2 and No. 3, which make up the rescue and evacuation platform, are both vertical and steep mountains with no roadbed or tunnel to pass through, the construction organization of the bridge abutments has brought certain difficulties.

[0081] To solve this problem, it is also necessary to ensure a safe distance of 6-8 meters between the bridge abutment and the cliff edge, such as... Figure 10 As shown, the present invention also includes a construction organization scheme for bridge abutments where there is no roadbed or tunnel access on the front and rear sides of the bridge. Based on an engineering example, the specific steps are as follows:

[0082] (1) From Provincial Highway 219, take the temporary access road for construction to reach the Shenshahe Bridge site, and then enter the main tunnel of Qingshiling Tunnel and Qinling Tiantaishan Tunnel through the tunnel construction inclined shaft and the tunnel vehicle cross passage.

[0083] (2) Excavate from the main tunnels of Qingshiling Tunnel and Qinling Tiantaishan Tunnel towards Shensha River Valley and exit in the opposite direction;

[0084] (3) Excavate a construction access road in the shape of a "tiger's mouth". The access road is about 4 to 5 meters wide, and the original mountain should be damaged as little as possible.

[0085] (4) After the construction access road is completed, three bridge abutment construction operation chambers with a width of 10m, a height of 5m and a depth of 3-5m will be excavated towards the mountain direction of Qingshiling and Qinling Tiantaishan. They are similar to "glasses-shaped" arch tunnels, with a net distance of 6m between the construction operation chambers.

[0086] (5) Construct the abutments of intermediate bridge No. 1, intermediate bridge No. 2 and intermediate bridge No. 3 in the construction operation cavern.

[0087] (6) After the bridge abutment is completed, the mountain is broken layer by layer from top to bottom, and the bridge abutment construction operation chamber is demolished.

[0088] The above-mentioned construction organization plan has great advantages for the No. 1, No. 2 and No. 3 bridges in the middle. It can protect the lives and health of workers to the greatest extent possible while minimizing damage to the mountain and preventing workers from being injured by falling debris.

[0089] When a disaster or accident occurs in the Qinling Tiantaishan Tunnel or Qingshiling Tunnel, the trapped personnel and vehicles need to be quickly diverted to the opposite tunnel via the Shenshahe Bridge (rescue and evacuation platform). Then, the trapped personnel and vehicles can be evacuated to Provincial Highway 219 via the tunnel's vehicular cross passage, tunnel construction inclined shaft, and temporary construction access road. At the same time, rescue vehicles on the rescue and evacuation platform can quickly reach the disaster or accident site, realizing the emergency rescue and one-way traffic maintenance functions of the ultra-long highway tunnel group.

[0090] To achieve the above functions, guardrails need to be installed at the transverse splicing edges of the left and right Shenshahe Bridges. These guardrails include reinforced concrete guardrails and open movable guardrails, with the open movable guardrails located within the gaps in the reinforced concrete guardrails. To determine the length of the open movable guardrails, such as... Figure 11 As shown, and in conjunction with an engineering example, the design process for an open-type guardrail is as follows:

[0091] According to the "Specifications for Highway Route Design" (JTG D20-2017) and the "Detailed Rules for Highway Grade Separation Design" (JTG / TD21-2014):

[0092] (1) The design speed of the turning lane at a level crossing should be 20-30 km / h, and the maximum should not exceed 40 km / h.

[0093] (2) When the design speed of the turning lane is 20km / h, the minimum radius of the circular curve of the turning lane at the intersection is 20m.

[0094] (3) When the radius of the curve of the turning lane is 20m≤R≤23m, the width of the turning lane at the intersection should not be less than 6m, and a lateral clearance of not less than 0.5m should be provided on both sides of the lane.

[0095] Considering that vehicle turning on the Shenshahe Bridge occurs during emergencies in the extra-long tunnels, the proposed design speed for the rescue and evacuation platform connecting lane is 20 km / h, with a turning radius of 20 m and a 0.5 m curb to meet the turning needs of heavy-duty trucks. Therefore, the minimum opening length of the movable guardrail for the left-line Shenshahe Bridge is 55.078 m, and for the right-line Shenshahe Bridge, it is 56.315 m. Furthermore, since heavy-duty trucks and articulated trains will have ample turning space and flexible turning maneuvers, and assuming no incidents or disasters occur in the extra-long highway tunnel complex, each of the left and right Shenshahe Bridges will only have one open movable guardrail, making closure simple and convenient.

[0096] Based on the above considerations, each of the left and right lines of the Shensha River Bridge is equipped with an open-type movable guardrail, with a guardrail length of 60m.

[0097] The Shensha River valley is narrow and deep with a steep gradient. Two large landslides exist upstream, and large boulders with diameters of 3-6 meters are present in the riverbed. To prevent large flying rocks from impacting the bridge piers and to protect the pile foundations from mudslides and strong currents during bridge construction or operation, a row of sloping, river-facing shoulder walls is required along the outer side of the piers. Furthermore, the distance between the riverbed edge and the foot of the mountain slope in the Shensha River valley is relatively small, and the rock surface at the foot of the slope at the bridge site is quite fractured. Without significantly encroaching on the riverbed or excavating the foot of the mountain slope with the sloping shoulder walls, it is difficult to construct the bridge piers.

[0098] To address this challenge, the present invention also includes a method for constructing bridge piers that are adjacent to a river and backed by a mountain, such as... Figure 12 As shown, based on engineering examples, various design measures were adopted, including riverside retaining walls, high-pile caps, and overlapping retaining walls. The specific steps are as follows:

[0099] (1) Clear the surface of the original mountain and construct a superimposed inclined shoulder retaining wall along the river. The retaining wall is 10m high. Excavate steps on the mountain behind the retaining wall. The steps can serve as the foundation for later filling the original mountain, while achieving the effect of minimizing damage to the original mountain. The setting of the retaining wall along the river and the superimposed retaining wall can effectively solve the problem of large rocks flying into the bridge piers in the "V" shaped valley with a large gradient, as well as the problem of pile foundation protection under the scouring of debris flow or strong water flow.

[0100] (2) Construct anchor bolts and grout them. The anchor bolts are 32mm in diameter and 6.2m in length. Embed steel casings for bridge pile foundations and fill the original mountain with C20 rubble concrete to build a bridge pile foundation construction platform.

[0101] (3) Construction of bridge pile foundations and high pile caps. The construction of high pile caps ensured the construction of bridge piers adjacent to the river and backed by the mountain while minimizing damage to the mountain slope.

[0102] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made to it in form and detail without departing from the scope defined by the claims of the present invention.

Claims

1. A construction rescue and traffic congestion evacuation system for ultra-long highway tunnel groups, characterized by: The project includes a left-line bridge, a right-line bridge, a rescue and evacuation platform, multiple extra-long tunnels, tunnel vehicular cross passages, tunnel construction inclined shafts, and a temporary / permanent construction access road. The left-line and right-line bridges are used to cross a "V-shaped" canyon and connect two extra-long, separate tunnels on either side of the canyon. The rescue and evacuation platform consists of multiple bridges arranged horizontally side by side, each independent of the others and connected laterally by longitudinal bridge deck expansion joints. The rescue and evacuation platform is located between the left-line and right-line bridges. Each of the two extra-long tunnels on either side of the "V-shaped" canyon has a tunnel vehicular cross passage and a tunnel construction inclined shaft. One end of the tunnel construction inclined shaft connects to the extra-long tunnel, and the other end connects to the temporary / permanent construction access road. Each of the two extra-long tunnels on either side of the "V-shaped" canyon has a tunnel vehicular cross passage, which connects the left-line and right-line tunnels, and the position of the tunnel vehicular cross passage corresponds to the position of the tunnel construction inclined shaft opening.

2. The construction rescue and traffic congestion evacuation system for ultra-long highway tunnel groups according to claim 1, characterized in that: The rescue and evacuation platform is spliced ​​to the left and right bridges on both sides through longitudinal bridge deck expansion joints. Guardrails are provided on the transverse splicing edges of the left and right bridges. The guardrails include reinforced concrete guardrails and open movable guardrails. A gap is provided in the middle of the reinforced concrete guardrails of the left and right bridges, and the open movable guardrails are set in the gaps.

3. The construction rescue and traffic congestion evacuation system for ultra-long highway tunnel groups according to claim 1, characterized in that: The left-line bridge, the right-line bridge, and several bridges of the rescue and evacuation platform are all continuous rigid frame bridges.

4. The construction rescue and traffic congestion evacuation system for ultra-long highway tunnel groups according to claim 1, characterized in that: The left-line bridge, right-line bridge, and multiple continuous rigid frame bridges of the rescue and evacuation platform are laid out along the mountainside on both sides of the "V-shaped" canyon. The bridge lengths and spans of many bridges are not exactly the same, including symmetrical continuous rigid frame bridges with side spans and asymmetrical continuous rigid frame bridges with side spans.

5. The construction rescue and traffic congestion evacuation system for ultra-long highway tunnel groups according to claim 1, characterized in that: The rescue and evacuation platform has a tunnel fire rescue chamber located at one end of the bridge in the middle position.

6. The construction method of the ultra-long highway tunnel group construction rescue and traffic congestion evacuation system according to claim 4, characterized in that: This includes construction methods for continuous rigid frame bridges with asymmetrical side spans and extremely small side-to-mid span ratios. The mid-span on the side with the smaller chainage has one more beam segment than the side span on the side with the smaller chainage. The key construction steps for the bridge are as follows: (1) After the pile foundation, pile cap, pier and box girder segment 0 are completed, install the hanging basket and repeat the symmetrical cantilever casting process until the box girder n is cantilevered. Segment 1, i.e. the largest symmetrical cantilever on the side of the small pile number; after the abutment construction is completed, a support is erected and pre-stressed next to the abutment of the side span, and the cast-in-place section of the side span is poured on the support; (2) Crossing n on the side of the small chainage Beam segment No. 1 and the middle span n of the small pile number side Counterweights were added to beam segment 1 simultaneously, with the weight of the counterweights being the same as the weight of the side span closure segment at the small pile number. (3) When the daily temperature variation is minimal, lock the closure section of the side span at the small pile number, weld the rigid frame, pour the concrete for the closure section of the side span at the small pile number, and then proceed with the closure of the side span at the small pile number n. The counterweight of beam segment 1 was unloaded synchronously, and then the support for the cast-in-place section of the side span at the small pile number was removed. (4) Cross n on the side of the small chainage No. 1 and n Permanent concrete counterweights were applied to the bottom slab inside the box girder segment No. 2, and the mid-span n at the small chainage was increased. The counterweight weight of beam segment 1 is increased from the weight of the side span closure segment at the small pile number to the weight of beam segment n. (5) The cantilevered mid-span beam segment n on the side of the small pile number, for the mid-span n on the side of the small pile number. The counterweight of beam segment 1 was unloaded simultaneously, and beam segment n of the middle span on the side of the large pile and beam segment n of the side span on the side of the large pile were cast in cantilever. (6) Remove the hanging basket, install the closure hanger, and when the daily temperature change is minimal, lock the closure section of the middle span and the side span of the large pile number, weld the stiff frame, pour the concrete of the closure section of the middle span and the side span of the large pile number, and then remove the support of the cast-in-place section of the side span of the large pile number. (7) After the bridge closure is completed, the closure section hangers are removed, the bridge deck system construction is completed, and the bridge ancillary facilities are installed.

7. The construction method of the ultra-long highway tunnel group construction rescue and traffic congestion evacuation system according to claim 1, characterized in that: The construction organization plan for the abutments of the multiple continuous rigid frame bridges that make up the rescue and evacuation platform includes the following specific steps: (1) From the local provincial highway, take the temporary construction access road to the bridge site, and then enter the main tunnel of the left tunnel and the right tunnel through the tunnel construction inclined shaft and the tunnel vehicle cross passage. (2) Excavate from the main tunnels of the left and right tunnels towards the "V" shaped canyon and exit in the opposite direction; (3) Excavate a construction access road to minimize damage to the original mountain; (4) After the construction access road is completed, the bridge abutment construction operation chamber is excavated in the mountain opposite to the "V" shaped canyon. (5) Constructing bridge abutments in the bridge abutment construction operation chamber; (6) After the bridge abutment is completed, the mountain is broken layer by layer from top to bottom, and the bridge abutment construction operation chamber is demolished.

8. The construction method of the ultra-long highway tunnel group construction rescue and traffic congestion evacuation system according to claim 1, characterized in that: The construction method for high-pile foundations located adjacent to rivers and backed by mountains includes the following specific steps: (1) Clear the original mountain surface, construct a superimposed inclined road shoulder retaining wall along the river, and excavate steps on the mountain behind the retaining wall to minimize damage to the original mountain. (2) Construct anchor bolts and grout, pre-embed steel casing for bridge pile foundation, fill the original mountain with rubble concrete, and construct a bridge pile foundation construction platform; (3) Construct bridge pile foundations and high pile caps.

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