On April 9, at the entrance of the Shaolingyuan tunnel, workers were unloading segments.
The Han-Ji-Wei Water Diversion Project is an overall, basic, public welfare and strategic major water conservancy infrastructure construction project to break the bottleneck of water resources in Shaanxi Province and achieve spatial balance in the allocation of water resources, and it is also the largest and far-reaching water conservancy project in the history of Shaanxi. The second phase of the Hanjiwei water transmission and distribution project was included in the 150 major water conservancy projects to be promoted during the national "14th Five-Year Plan" period. Recently, the reporter walked into the front line of project construction to explore the story of water control and rejuvenation in our province.
On April 9, at the construction site of the Shaolingyuan tunnel in Chang'an District, Xi'an, a large crane unloaded pieces of reinforced concrete segments weighing 3 tons from the transport vehicle to the rail truck, and these segments will be sent to the tunnel ...... "This season is very suitable for the construction of water conservancy projects, and it is the 'golden period' of water conservancy construction in a year, and we are doing our best to make progress." Meng Jiugang, chief engineer of the Shaolingyuan Tunnel Construction Standard Project of the South Trunk Line of the 12th Bureau of China Railway Twelfth Bureau, said.
Under the strong leadership of the Provincial Party Committee and the Provincial Government, important results have been achieved in the first phase of the water diversion project from Han to Weiwei, and the second phase of the water transmission and distribution project is also in full swing. Our province will coordinate and promote the construction of the first and second phases of the Han-Ji-Wei project, based on the actual situation and the needs of the water-receiving area, coordinate the efforts of all parties to solve engineering problems, provide service guarantees, and speed up supporting construction, so as to ensure that the project is open to water as scheduled, and give full play to the comprehensive economic and social benefits as soon as possible.
On the land of Sanqin, tunnels penetrate mountains and rivers, pipelines extend vertically and horizontally, bridges fly north and south, and Shaanxi is setting off a great water conservancy boom.
Break through the water and sand layer
Take multiple measures to overcome the "roadblock"
The Shaolingyuan Tunnel is the control section of the second phase of the Hanjiwei Diversion Project, which has been plagued by water and sand layers since its construction. On April 1, the reporter entered the tunnel to find out.
After about 30 minutes of taking the rail battery car, the reporter arrived at the face of the tunnel, and a 150-meter-long "steel dragon" was struggling to excavate. At the very front of the TBM, the cutterhead rotates slowly against the ground, and with a "click" sound, the soil and sand are crushed into debris into the soil silo and transported by the screw below to the trolley conveyor belt.
At the slag outlet of the screw machine, there is mud gushing out from time to time. Every 1.5 meters of excavation, workers have to clean up the site. They rolled up their trousers, rolled up their sleeves, and waded into the water, some of them pumping the muddy water into the trolley with a pump, and some of them nervously connecting the water pipes, connecting the tracks, and unloading the segments. In the hot and humid environment, it didn't take long for the workers to sweat profusely and their uniforms to be soaked.
After the cleaning is completed, the segment assembler grabs the prefabricated segment staggered joints and splices, and finally forms a circular tunnel pipe at the end of the shield. From tunnelling to installation of segments, each cycle takes two hours.
"Normal construction only takes one hour, but the mud gushes into the segment installation area, which requires a lot of time to clean, which has become a 'roadblock' for the progress of the project. Meng Jiugang said.
Meng Jiugang explained that the Shaolingyuan tunnel is located between the Wei River and the Chan River, and most of the cave body is between 43 and 77 meters below the groundwater line. The total length of the tunnel is 8.6 kilometers, of which 2.1 kilometers are in the coarse sand layer in the high-pressure water-rich medium, the sand content is 50%-80%, and the rest is water, which is rare in China.
In order to cross this water and sand layer as soon as possible, Shaanxi Provincial Hanjiwei Engineering Construction Co., Ltd. (hereinafter referred to as "Hanjiwei Company") and the participating parties have organized experts to come to guide them many times. After repeated tests, the expert group formulated effective measures such as grouting to block the water inflow, adding chemicals to improve the muck, increasing the pumping of equipment, etc., and also set up a filter press outside the hole, so that the muck can be transported quickly and improve the work efficiency.
This sense of urgency is also transmitted to the workers. "They work in two shifts 24 hours a day, eat on the shield machine, and rest in the board room of the construction team. Everyone is firing on all cylinders to grab progress. Meng Jiugang said.
Liang Jintao, a "post-00" guy from Shanxi, has not been home since the Chinese New Year, and his daily work is to stare at the screen in the cab of the shield machine of less than 2 square meters, pay attention to data changes and revise the tunneling parameters in time.
Liang Jintao, who has already participated in the construction of two subway projects, is already a veteran in the operation of shield machines, but he still does not dare to slack off: "This project is a water conveyance tunnel, with a large burial depth, a small cross-section and abundant groundwater, which is a challenge for me. Now is the critical period of tackling tough problems, I must control the attitude and parameters of the shield machine to excavate safely. ”
"At present, we are able to excavate 910.5 meters per day, which is twice as high as at the beginning of entering the water and sand layer, and there are still 302 meters left to cross and resume normal construction. I believe that with positive and effective countermeasures and conscientious workers, we will soon be able to 'get out of trouble'. Meng Jiugang said with confidence.
Special class advancement
The construction of the southern trunk line has been improved and accelerated
Outside the Shaoling Plateau tunnel, it was raining lightly. On April 1, the special team for the construction progress management of the second phase of the project of Hanjiwei Company was carefully checking the product parameters of a batch of water transmission segments.
"Is this concrete segment seeping?"
"No, he's precast from C50 impermeable and freeze-resistant concrete. ”
"How well is the bead seal on the segment?"
"The black strip fits flat and seals well, while the yellow expanded strip absorbs water and prevents leakage. ”
……
The inspection of the special class put the stability of production and the prevention and resolution of risks in a prominent position, and also reassured the construction party.
Why is there a special team? Because tunnels are difficult to dig and management is difficult to coordinate.
In the planning stage of the southern trunk line of the second phase of the Han-Ji-Wei diversion project, in order to leave enough space for urban development in Xi'an and reduce the impact on the ecology of the valley at the northern foot of the Qinling Mountains, the project plans to excavate a water conveyance tunnel from the shallow mountainous area on the northern slope of the Qinling Mountains. However, the geological conditions here are complex, the rocks are broken and loose, the groundwater is abundant, and the tunnel construction is converging deformation, landslides, water gushing, and mud gushing...... Geological disasters occur frequently, seriously affecting the progress of project construction.
"There used to be a branch cave in the Qinling alluvial fan, the loess in the cave met the water into mud, the face of the tunnel has no self-stabilizing ability, the tunnel was dug for a few days, and it collapsed nearly 15 meters. Li Jinlin, deputy manager of the Qinling Branch of the Han Jiwei Company, said, "During the construction, the construction personnel have been engaged in a 'tug-of-war' with the complex geology in the tunnel, and have tried many ways to remedy it, with little effect, which is a headache." ”
In order to ensure the completion of the second phase of the project as scheduled, the company set up a special class for the construction progress management of the second phase of the project in a timely manner. The company's leadership team led the team to go to the front line, communicated with the design, construction, supervision and other personnel in a timely manner, optimized the construction management procedures, solved the contradictions in the construction of the project, and actively connected with the local government to coordinate and solve the problems of land acquisition and demolition.
The world is wide for a change of thinking.
Since the beginning of this year, in accordance with the requirements of the special class, Qinling Branch has changed passive defense to active attack, actively summarized the experience of project construction, communicated in-depth with all participating parties in advance, made good plans, solved problems such as deformation and landslide, and solved the geological problems of Huangwu Tunnel in advance.
In order to ensure the progress of the project, Qinling Branch formulated a work plan, clarified the work idea of "opening as much as possible, as soon as possible, and starting construction as soon as possible", and comprehensively sprinted the annual project construction goal.
"We have a special person responsible for solving the remaining problems such as business and contract settlement of the branch tunnel standard, ensuring that the construction unit of the branch tunnel quickly exits the site and the main tunnel construction unit enters the site quickly, so as to 'open as much as possible'; Wang Xin, deputy manager of Qinling Branch, introduced.
At present, the 9 branch tunnels completed in advance of the Huangwu Tunnel of the South Trunk Line have fully completed the handover of the working face, and 18 tunnel excavation faces have been added at one time, and the main tunnel construction unit has begun to enter the construction. "The 18 working faces are going hand in hand, and the construction speed of the South Trunk Line will be greatly improved. Wang Xin said.
Spatial balance
Support the high-quality development of cities
If the water of the Han River wants to nourish Guanzhong on a larger scale, it needs to cross the Wei River and the Jing River and continue northward. In order to facilitate the water transmission of water from the north trunk line of the second phase of the Hanji-Wei project, the builders will erect two pipe bridges on the surface of the Jing River and the Wei River to facilitate the passage of water from the Han River.
On April 1, in Niuyang Village, Taiping Town, Airport New Town, Xixian New District, the smooth and wide bridge deck of the Jinghe Pipe Bridge on the North Trunk Line extended into the distance, and workers were orderly carrying out the hanging basket hanging pouring construction operation.
"We are working hard to speed up the construction, and it is expected that the Jinghe pipe bridge will be closed by the end of August, and the two water pipes will be laid by the end of November. The Weihe River Pipe Bridge will also be completed in 2025 and will be ready for water access. Xie Long, technical director of the VII standard project department of the North Trunk Water Pipeline Construction of the Second Phase of the Hanjiwei Project of the Fifth Bureau of China Railway, said.
With the attitude of "not stopping for a moment, not missing a day", the builders have paid close attention to the excavation of tunnels, pipeline laying, bridge construction and other work of the North and South Trunk Lines of the Hanji-Weihai Trunk Line, and it is expected that the second phase of the Hanji-Weihai project will be completed in 2026, which can provide comprehensive water supply to Xi'an and Xianyang.
After the completion of the Han-Wei-Wei diversion project, 1.5 billion cubic meters of water will be diverted from the Hanjiang River every year, which will solve the industrial and domestic water problems of the four key cities of Xi'an, Xianyang, Weinan and Yangling, as well as 11 small and medium-sized cities along the Weihai River, Xi'an Jingwei Industrial Park and Weibei Industrial Zone. More importantly, a "north-south allocation" water transmission channel will be added in the main skeleton center of the national water network, which will play an important role in achieving spatial balance in the allocation of water resources and ensuring high-quality economic and social development.
"Urban development should adhere to the principle of 'determining the city by water, the land by water, the people by water, and the production by water', and water resources directly affect the urban planning level and industrial layout of Xi'an and even the urban agglomeration in Guanzhong and northern Shaanxi. The Han-Ji-Wei River Diversion Project provides water resources support for the development of Xi'an National Central City, Xi'an Metropolitan Area and Guanzhong Plain Urban Agglomeration, and provides necessary conditions for the state to lay out important scientific research, education and industrial bases in Xi'an. At the same time, the Han-Ji-Wei diversion project will provide 400 million to 600 million cubic meters of water for the national energy and chemical base in northern Shaanxi to draw water from the main stream of the Yellow River every year through the replacement of water rights. Tian Yangjun, Secretary of the Party Committee of Han Jiwei Company, said.
The surging water of the Han River is getting closer and closer, which not only opens up a new situation of water use from the south to the north, but also is the key to improving the city's energy level.
At the same time as the construction of the Hanji-Wei diversion project, Xi'an, Xixian New Area, and Xianyang have also accelerated the construction of reservoirs, water plants, water supply pipelines and other supporting projects, and have made every effort to undertake the water supply from the Hanjiang River: the water plant in the southwest suburbs of Xi'an City will use the water source of the Han-Ji-Wei River to meet the water needs of the industry and people's livelihood in the Yiyi District, High-tech Zone, Fengdong New Town and Fengxi New Town; The Jinghe New Town will play an important role in the overall development of the region and the attraction of investment, and the water supply project will increase the ecological water volume and environmental capacity of the Weihe River Basin and greatly improve the regional ecological environment while ensuring the residents' domestic water supply......
A new pattern of water resources is being formed at an accelerated pace, and a trickle of clear water will benefit the people and continue for future generations. (Xiao Qianwen/Photo)