Study On Pipe Jacking Construction Control Of Existing Railway Corridor Under Existing Pipeline

With the rapid development of the urbanization process,the integrated pipe gallery,as a new form of underground construction,has been increasingly valued by the state and society.Nowadays,different types of integrated pipeline corridors have already started to break ground.They have solved the problem of “black pollution” caused by the continuous “opening” of urban roads,eliminating the influence of urban “spider web” type pipeline laying and creating a good ecology.Features such as systems are increasingly suited to the needs of social development,and the pipe jacking method is one of the well-established construction techniques that avoids large digging and large filling and adapts to complex areas.At present,there are a lot of researches on the construction of circular cross-section pipe jacking in China,but there are few rectangular section studies.Only the CCCB bureau successfully implemented the rectangular pipe jacking integrated pipe corridor.Moreover,the rectangular jacking pipe is more complete than the circular cross section.The use of 20% of space utilization has greatly increased the number of pipeline routes.Therefore,this paper studies the influence of the rectangular pipe jacking on the deformation of the railway-related soil layer in a complex area by studying the rectangular integrated pipe corridor under the railway in the Hada Bay area of Jilin Province.In this paper,empirical formulae and finite element simulations are used to simulate two types of rectangular cross-sections of 9.0m×4.4m and 6.0m×5.0m at three types of soil cover thickness: 3m,6m,and 11 m.Corridor cross-sections were compared and analyzed.At the same time,the FEM was used to simulate and compare the two types of settlements from soil settlement,cost-effectiveness,and space utilization.The cross-section of 9.0m×4.4m cross-sections under 11 m soil cover thickness was selected as the most comprehensive.Excellent construction plan,and then through the two conditions of advancing and propelling,analyze the influence of the soil properties of the two railway tracks under the long map and the long-distance high-speed railway piers,and make reasonable control of soil and pipe rectification.Measures and draw the following conclusions:(1)During the construction of the pipe jacking,the soil layer within the triple pipe diameter has a greater impact,and the soil layer outside the triple pipe diameter has less influence.Under different soil cover thickness,the greater the thickness of the coversoil,the smaller the settlement deformation.(2)The size of the rectangular section has a great influence on the soil layer.The larger the size,the greater the settlement deformation.At the same time,the length and width of the section not only have a great influence on the deformation of the soil layer in the cross section and longitudinal section of the soil layer,but also the horizontal displacement of the soil layer.There is also a great relationship between size and location.(3)The formation of earth layers for unloading soil arches is beneficial to reduce the settlement of soil layers and plays a role in strengthening soil layers.However,the stability of soil arches is also closely related to the above-mentioned railway load and soil properties.(4)During the construction of the pipe jacking,under normal circumstances,the soil layer in front of the pipe jacking machine swells up and sinks behind,but in the actual construction,due to the dual effects of the train load and the unloading arch,the railway embankment will rebound accordingly.It is necessary to ensure the accuracy of various parameters of the pipe jacking during construction.(5)The loss of soil layer has little effect on the horizontal displacement of the soil,while other pipe-jacking construction techniques such as grouting pressure,friction,and additional thrust play a decisive role in the horizontal displacement of the soil layer.(6)When the pipe jacking is advanced,there is an offsetting effect between the train load and the propulsion force.When the propulsion stops,only the train load acts alone,which makes the uplift of the soil on both sides worsen.(7)The top pipe inlet needs to be grouted in the range of 0-3m to reduce the impact of the "back soil effect".The export needs to adopt the infrared drawing point method to avoid the "heading" phenomenon,and to increase the cutting strength of the pipe jacking machine to prevent " Head up phenomenon.