Mechanical pipe jacking construction method is a widely used Trenchless Technology in pipeline engineering construction, in which the technical level and maturity of concrete pipeline construction are higher.
the specific construction shall be comprehensively confirmed according to the actual environment of the construction site, pipe diameter and length, soil quality, economy and other factors.
Pipeline engineering is an important part of municipal engineering.
2 overview of trenchless construction technology trenchless technology is to use advanced geotechnical drilling technology and equipment to change the way of large-area excavation of soil in traditional pipeline construction, and try not to excavate or less by means of guiding and directional drilling, so as to complete the replacement, laying and repair of underground pipelines, which will not affect the traffic, vegetation It has an impact on the normal life of businesses and residents, and has good social benefits.
The waste slag generated during pipe jacking construction is divided into dry slag and wet slag, and targeted treatment and prevention shall be adopted according to different types of waste slag.
The project has many construction characteristics, such as long construction cycle, large quantities, high investment cost, large amount of personnel and equipment involved.
The traditional municipal pipeline engineering adopts excavation construction method, which will not only affect the surrounding traffic and commercial activities, but also affect the normal life of surrounding residents.
the construction steps are usually the following three steps.
The trenchless construction link is mainly divided into two links: first, the earth is moved in the direction of construction, such as deviation making, hole opening and straight keeping; Secondly, the opening diameter shall be strictly controlled according to the engineering construction requirements, the hole shall be expanded according to different grade requirements, the hole wall shall be strengthened and thickened as necessary, and the pullback expansion shall be completed.
This construction method is to guide and test by computer during construction, design and excavate holes with the same curve, and move the pipeline out of the guide hole, so as to complete the construction of the whole pipeline project..
Trenchless technology can not only be used for the laying, repair and replacement of underground water supply and drainage pipelines in municipal projects, but also for the modification of underground cable lines, which has good application value [2].
On the premise of ensuring that the pipe jacking meets the length requirements, the number of working wells and receiving wells can be reduced as much as possible, the quantities can be reduced, and the impact of excavating working wells on the surrounding environment can be reduced.
In addition, sufficient pipe jacking construction survey shall be done in advance to obtain accurate measurement data, and the centerline, elevation and slope of pipe jacking shall be strictly controlled according to the measurement data.
Under the background of the continuous development of China’s construction industry and construction technology, trenchless construction technology is more and more widely used in the construction of municipal pipeline engineering.
At present, when 600mm ~ 4000mm pipelines are laid in a straight line, concrete pipelines, clay, etc., most pipelines are constructed by mechanical jacking.
In the process of pushing the pipe, the soil entering the pipe shall be discharged in time until the pipe jacking operation is completed.
4 specific application mode of trenchless technology 4.1 pipe jacking construction technology pipe jacking construction technology first excavates the working pit, then installs the jacking equipment in the working pit, uses the jacking force generated by the equipment to push the pipeline into the soil according to the design slope, and transports the ejected earthwork away.
4.2 construction principle of pipe jacking construction after construction, first dig a well at the pipe side and install guide rails in the excavated foundation pit.
During construction, the construction well shall be set in the middle of pipe jacking as far as possible to facilitate its movement during construction.
Finally, the use of trenchless construction technology in municipal pipeline construction can obtain pipeline pits with better precision, greatly improve the construction quality of municipal pipelines, avoid contact with surrounding buildings, and ensure that the pipeline construction meets the design requirements [1].
Second, install mechanical equipment.
Usually, rails are installed on wood or concrete technology, and pipes are installed on rails [3].
It plays a very important role in urban daily water use, flood control and waterlogging drainage.
This construction method has little damage to the road surface, can also protect the underground pipeline, prolong the service life of the underground pipeline, and has good economic and social benefits.
Before pushing the reinforced concrete pipe into the soil, the surface and interior of the pipe shall be fully cleaned to ensure that there are no sundries inside.
4.3 with the continuous development of trenchless technology, the application scope of traction pipe construction technology in the construction industry continues to expand, especially in the construction of large-scale river crossing projects, municipal pipeline projects, environmental protection and other aspects, highlighting its unique technical advantages [4].
However, the developing countries’ understanding of the importance of trenchless technology is constantly improving, the domestic research on Trenchless Technology is also deepening, and the scope of application in municipal engineering is also expanding.
With the accelerating process of urbanization in China and the increasing population in the city, it not only greatly promotes the urban economic growth, but also brings great operating pressure to the urban municipal engineering.
However, whether the laying of new pipelines or the repair of old pipelines will affect the original traffic, commercial activities and residents’ normal life at the construction site to a certain extent.
Secondly, since the trenchless technology will not use large-scale excavation equipment during construction, the flexibility of construction is greatly improved.
In the pipe jacking operation, not only the construction environment shall be surveyed in detail, but also the geological conditions along the shaft shall be taken into account.
At present, the trenchless technology in the domestic construction industry has not reached the mature level, and there are still great deficiencies compared with countries with mature technology.
Based on this, this paper summarizes the trenchless construction technology, and analyzes its application in municipal pipeline construction in detail, in order to provide reference for relevant personnel.
It can carry out construction even in a narrow environment, minimize the impact on the normal life of surrounding residents, and has good social benefits.
According to the drilling route formulated in the underground drilling construction scheme, install the relevant mechanical equipment at the predetermined opening position, then excavate the incident operation pit, do the necessary protection, support, reinforcement and drainage, and install the drilling equipment.
Common construction methods include horizontal guided drilling method, pipe jacking method, micro tunnel method, etc.
Introduction municipal engineering is the basic engineering of urban operation, which is closely related to the life and production of urban residents and plays a very important role in driving the comprehensive development of the city.
Third, drilling construction.
However, the use of trenchless technology is highly dependent on excavation equipment.
The specific construction methods include manual pipe jacking, water jet jacking and extrusion jacking, mechanical pressurization, etc.
3 application value of trenchless technology first of all, compared with the traditional municipal pipeline excavation technology, trenchless technology mainly uses advanced drilling machinery and equipment to drill holes and lay pipelines in the underground environment.
First, survey.
Push the prefabricated reinforced concrete pipe into the soil with hydraulic jack, and retain the tool pipe with horizontal thrust as the core.
It is also necessary to bury tool pipes or excavator hoses in the two working pits.
It is less dependent on labor and large excavation equipment, which can greatly reduce labor cost and equipment rental cost, reduce capital investment and obtain better economic benefits.
Municipal pipeline engineering is one of the indispensable infrastructure in urban modernization.
In recent years, with the deepening application of Trenchless Technology in municipal pipeline construction, the impact of the above related problems has been effectively improved.
Before construction, a comprehensive and detailed survey shall be carried out, including the soil conditions of the construction environment, the layout of surrounding pipelines, the construction of surrounding buildings and structures, etc., and then a scientific underground drilling construction scheme shall be formulated in combination with the construction needs and survey results of municipal pipelines, so as to provide necessary data reference for the construction of municipal pipelines.
If the construction terrain distance is long or the complexity is high, the hoisting construction method must be adopted, supplemented by necessary protective measures of green environmental protection building materials, such as mud jacket lubrication and laser correction, so as to ensure the construction quality.
