Expressway, An Chuan, along the ancient tea-horse road, the camel heard the commercial footprint of Ma Si, crossed the Hanshui River and Bashan Mountain, and accompanied Ren River to Sichuan. It is a golden channel to expand economic and cultural exchanges between North China, Northwest China and other provinces and cities in China and Southwest China. It is the last section of Baomao Line of expressway National Network in Shaanxi Province, an important part of "2367" expressway Network in Shaanxi Province, and also a key construction project in the 11th Five-Year Development Plan of Shaanxi Province. The project invested 9.5 billion yuan, including 300 million dollars from the World Bank.
The total length of the line is 105km, which consists of two construction projects: Ankang to Maoba and Maoba to Shaanxi-Sichuan boundary. Bridges 1 1 1, 23 tunnels, four lanes in both directions, subgrade width of 24.5m, and design speed of 80km/h. Starting from xikang high-speed, it meets the Ten-day Expressway. The proportion of bridges and tunnels accounts for 80% of the total route, which is the highest in expressway.
Its completion and opening to traffic marks the completion of Baomao Line in our province. Hurongxi in Hubei, Yaxi in Sichuan, Changhua in Hunan and An Chuan in Shaanxi are typical representatives of the difficulties in the construction of expressway in mountainous areas of China. An Chuan expressway is called "unprecedented" by experts and peers because of its difficulty. Material transportation in the reservoir area is difficult; The canyon is too steep to fight; The snowstorm closed the road and exhausted the ammunition. Before the flash flood hit, all the work was in vain ... The complex geological and natural environment of Daba Mountain tested the perseverance and wisdom of Shaanxi traffic people round after round.
This is a construction project in expressway, a mountainous area with the most difficult construction conditions.
"Difficult" is the dangerous road with high mountains and steep slopes, which makes it difficult to transport building materials. Due to the limited traffic volume of railways and waterways, highway transportation has to cross two high-altitude peaks, Phoenix Mountain and Mixiliang Mountain. Provincial Highway 3 10 was built in the early 1970s, with low grade, large longitudinal slope, poor road conditions and many bends. This most important traffic lifeline supporting the whole project construction, which surrounds the valley and cliff, is called "snake road" by drivers.
What is "difficult" is that the bedrock of the mountain is broken and collapses in a large area. The hinterland of Bashan Mountain has broken geology and poor stability. 90% of the longitudinal bridges along the Hanjiang River are erected in the reservoir area, and the water level fluctuates, the bedrock is broken, and the mountain is in a state of limit equilibrium.
What is "difficult" is that due to geographical and geological factors, the construction site of each bid section is narrow, the material preparation site is narrow and the storage site is smaller. The prefabricated beam yard is scattered on the hillside of 60 degrees, only 30 to 50 meters, so it is impossible to carry out large-scale processing operations, and the technical force and equipment cannot be carried out in an orderly manner. This is a disaster-prone mountain expressway construction project.
At the beginning of 2008, a large-scale snowstorm swept across the country, and the snow closed the mountain, and the material supply was in a hurry.
In mid-April 2008, the first flood hit 25 construction sites along the route. Equipment, materials and access roads were washed away.
In 2008 alone, floods washed the construction site 13 times.
In May, 2008, the Wenchuan earthquake, the railway stopped the transportation of goods, and the transportation of materials was interrupted again. 2010 "7.18" catastrophic flood caused serious losses in mixiliang tunnel.
From September 2008 to October 20, 2008, the engineering construction in An Chuan suffered more than 30 floods. Due to the limitation of road and railway traffic, waterway transportation has become another lifeline of An Chuan project. 90% of aggregate, cement and equipment in the whole line should be transported or transshipped by ship. Among them, 14 bid rented 1 1 large marine materials as soon as it entered the site. In order to cross the 15 standard, six floating cranes were used in the water, and a 6 18m steel trestle was built to transport materials and equipment. Almost all the building materials in the whole project are transported back to the processing site along the waterway, and then transported to the construction site through the waterway.
It can be said that there are three modes of material transportation in expressway, An Chuan: train, ship and car. Shaanxi Provincial Department of Transportation requires An Chuan expressway to be built into a "high-quality boutique project, an eco-environmental protection project, an innovative demonstration project and a standardized management project" to achieve "five satisfactions"-to satisfy the provincial party committee, the provincial government and the people of the whole province, the drivers and passengers, the environmental protection department and future generations, the local government and people along the route, and the World Bank. Engineering quality is a long-term plan.
The Foreign Investment Department of the Provincial Department of Transportation and the An Chuan expressway Management Office focus on strengthening the fine management of precast beams, pier appearance, protective engineering appearance, deck pavement, continuous rigid-frame bridge construction technology, concrete maintenance, tunnel drainage system and abutment back backfill. Carefully investigate the common quality problems of high slopes, tunnels and concrete, formulate treatment measures, and carry out special treatment on the qualified rate of 10 weak quality indicators. Management office, the director's office quality inspection team at ordinary times to check and spot check, check and compare every month. Each station conducts road inspections every day, and the key processes are on standby all the time.
The bridge construction of An Chuan Project follows the principle of "learning from others' strengths and building independently", and has achieved the perfect leap from cliff to cliff again and again. 80% of the bridges cross the river, along the river or across the beach, extending in Daba Mountain. During the construction period, firstly, there are frequent floods; Second, the water level is unstable, and the elevation difference is artificially adjusted to 20 to 30 meters, making it difficult to locate the water construction platform; Third, the dam hinders navigation, large-scale water equipment cannot enter, and technical forces and equipment cannot be deployed in an orderly manner; Fourthly, the rock at the bottom of the reservoir area is hard diabase, so it is very difficult to drill footage. Bridges along the Hanjiang River and Renhe River are like ants moving, moving materials bit by bit, falling inch by inch, climbing high and climbing low over and over again. The builders are composing a magnificent bridge song in this difficult environment.
The bridge piles in expressway, An Chuan are half in the mountains and half in the water. The site on the mountain is narrow, and it is difficult for large machinery to enter because of aerial work. In water, it faces the problem of deep-water pile foundation. 12- 15 is marked with a bridge, and the distance is near 1 1 km. Most of the pile foundations are constructed in water, and each pile foundation should be equipped with a water construction platform. The river bottom is uneven in hardness, the pile foundation is difficult to form holes or eccentric holes, the diabase is extremely hard, and it is difficult to drill with a bit. Normal pile foundation construction can be completed in half a month, but Ma Jinren and the pile foundation of pier 39 of the bridge have been working for a whole year.
Ziyang Hanjiang Bridge is the most beautiful scenery on the 3000-mile Hanjiang River, with a total length of 2106m, a pier height of 74m, a pile foundation depth of 40m and a span of170m. This is the most difficult pile foundation construction in the shallow overburden of bridges in our province. After many demonstrations, the method of "deep water shallow overburden river bottom grouting drilling construction" was adopted to complete the drilling operation, setting a new record for industry selection. A bridge is a link and a leap.
There are 65,438+02 T-shaped rigid frame bridges along the Hanjiang River and Renhe River, the largest tributary of the project, spanning Yinghu Lake, Hanjiang River and Renhe River. The components and pouring materials of these 12 bridges are carried up the mountain bit by bit by people's shoulders and caravan camels. The construction of these continuous rigid-frame bridges along the river has gone through hardships. Heigou continuous rigid frame bridge with high dam can be said to have been soaked by flood.
In 2008 13, floods flooded again and again. Builders, however, with strong fighting spirit and perseverance, re-erected their piers after repeated floods; After repeated floods, bridges and culverts flew over again. Expressway, An Chuan, is built along the Hanjiang River and Renhe River, with rich underground water system, heavy rainfall above ground and broken geological conditions. There are 23 tunnels in the whole line, accounting for 33% of the line. There are many tunnels and it is difficult to cross. The Songjialiang Tunnel, which is more than 900 meters long, is called "the most difficult short tunnel to drill". Powdered phyllite and mud keep gushing out, landslides and altitude keep sinking. Huoshenliang tunnel is located in the ancient landslide accumulation body, which is a landslide. The phyllite of Fenghuangshan Tunnel has been treated for more than a month. Yaoshuliang tunnel is also a broken accumulation body, and the mountain will sink when it rains. The maximum water inflow of the whole line is Maoba Tunnel 1, and there are 32 large water inflow, which is 17 times of the designed water inflow ... Expert argumentation, scientific research team, assault team, in this tunnel battle, the builders have made hard efforts and outstanding wisdom. The biggest difficulty in expressway, An Chuan-Mixiliang Tunnel, with a total length of nearly 8 kilometers, is the longest tunnel in expressway, An Chuan and the third longest tunnel in Shaanxi section of Baomao Line. At first, it was entangled in the flood, and then it fell into the predicament of mud collapse. Large-scale landslide, water gushing, mud outburst and the 1 1 fault zone with complex geological structure make it difficult to drive every foot of Mixiliang Tunnel.
"No destruction is the greatest protection", which embodies the environmental protection concept that traffic people hide roads in nature. 80% of the bridge and tunnel planning has laid a great environmental protection concept for An Chuan: don't disturb mountains and rivers, respect ecological balance, and let animals and plants live in harmony and happiness with expressway. In this piece of green mountains and green waters, An Chuan Road will become the best environmental protection for Shaanxi highway construction.
In An Chuan, especially high slopes, there are 162 slopes in the whole line, including 63 high slopes, of which the highest is 70 meters; Steep slope 109, ranging from first grade slope to eighth grade slope. Geological diseases include landslides, collapses, slumps, falling rocks and mudslides. During the construction, the principle of excavation and protection is adhered to, and comprehensive control measures such as increasing anti-slide piles, making slopes with wire gabions, supporting seepage ditches and increasing inclined drainage holes are taken to stabilize the mountain.
The high slope project in An Chuan has withstood the test of "7. 18" flood in 20 10. Tens of thousands of construction teams have entered the Han River, and the self-discipline of this huge "pollution source" has become an important thing. From the management office to the construction and supervision units, the "Safety and Environmental Protection Department" was established. The management office also entrusted Ankang Environmental Protection Monitoring Station to monitor the environment during the project construction and provide professional guidance at any time. The line passes through the water surface of Hanjiang River and Yinghu Wetland Nature Reserve, and the management office stipulates that it is not allowed to borrow soil, stone or dig wounds in these areas. All the pile foundations on steep slopes are excavated manually, and the light abutment pile foundation replaces the enlarged foundation to reduce the excavation amount. Walking into the construction site, you can see the grass and the pier of the bridge close at hand, dancing in the wind. A section of Xiaoheba Bridge in Lin Ziyang County changed from subgrade to bridge. By boat along the Han River, you can see that the bridge passes through the edge of the natural chicken-claw-shaped mountain, without occupying cultivated land or cutting mountains, and rows along the river, like a rainbow in the water. Since the project started three years ago, the whole line has used 4 million cubic meters of concrete, 3.6 million cubic meters of crushed stone, 2.5 million cubic meters of sand, 2 million tons of cement and 420,000 tons of steel ... This is not just a string of figures, but also includes the hardships, sweat and responsibilities of every ordinary builder.
The above is the introduction of Construction Network to the construction difficulties in expressway, An Chuan. For more information about expressways, please pay attention to the architectural knowledge column of Zhong Da Consulting.
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