Pipe Jacking Construction Geotechnical Environmental Effects Monitoring And Control Technology Research

Pipe jacking construction method compared with traditional Ming dig buried pipe construction method has little interference environment, high construction efficiency, low comprehensive cost a lot of advantage; At the same time, the pipe jacking construction technology is complex, big shortcomings, such as security risk, especially the pipe jacking construction process and pipe jacking construction after the completion of the construction within the scope of influence of land subsidence, horizontal displacement, etc., could lead to a nearby existing buildings, structures, underground municipal pipeline damage, damage, and even cause secondary disasters occur, causing serious economic and social consequences.Combined with iron kaifeng district in the southern district of longhai along the drainage engineering example, the mechanical of disturbance of soil around the pipe jacking construction are studied, through the analysis to the actual measured data settlement of surrounding soils, lamination settlement and pore water pressure change rule; Using ABAQUS finite element simulation software to establish pipe jacking driving model, and then the simulation results and the actual monitoring results, verify the reliability of the model. And then change the construction parameters, the construction technology of parameter optimization problem, for the future similar geotechnical engineering under the condition of pipe jacking engineering provide certain theory reference and empirical guidance.Through the field monitoring data and numerical simulation analysis of ABAQUS, mainly the following conclusions:1. The pipe jacking construction will cause land subsidence, soil pipe shaft above the maximum settlement and the smaller the farther distance pipe shaft settlement, settlement curve basic comply with the principle of Peck curve; Pipe jacking machine before the patch experience slight bulge in the machine through the rapid subsidence of soil; Layered settlement of soil caused by pipe jacking construction presents a certain regularity, the final settlement of layered monitoring point related to its embedding depth, pipe jacking construction will lead to the adjacent soil vertical difference of deformation, and showed obvious "escapes" phenomenon, namely the surface subsidence is less than deep settlement, which will bring hidden dangers for ground deformation control; Pipe jacking construction can make the change of soil pore water pressure in the body, when the machine through the pore water pressure will have a certain degree of rise, tube wheelbase and the distance from the closer, the greater the degree rise after machine through back to normal levels.2. The pipe jacking construction quantity of overbreak and ground load will cause great influence to the ground settlement. Pipe jacking overbreak volume, the greater the ground load, the greater the the ground settlement. Through practical engineering monitoring results and the comparison of simulation results, found that 10 kpa dug 30 mm load model of numerical simulation results and the actual monitoring results is consistent, and the engineering parameters and is also of practical engineering, to verify the overbreak is the main cause of land subsidence.3. When the pipe jacking construction synchronous grouting can effectively control the ground subsidence. Grouting pressure and grouting volume are has a great influence on the grouting effect, too large and too small is unfavorable for the construction, the construction should be based on the specific construction conditions to choose the most reasonable grouting pressure and grouting amount, so as to better control the ground surface settlement. According to simulation results, the subsidence control effect good grouting pressure for soil water pressure pipe jacking is 1.2 ~ 2 times, grouting quantity for the theory of overbreak volume 1 ~ 1.5 times.