Cement pipe-jacking construction is an underground pipeline construction method developed after shield construction. It does not need to excavate the surface layer, and can cross roads, railways, rivers, ground buildings, underground structures and various underground pipelines. It is more and more widely used in the construction of water supply and drainage, gas, electricity, communications and other pipelines. However, the construction equipment, technology and management level of the cement pipe-jacking construction unit are uneven, and some problems often occur in the construction, affecting the construction quality. The problems and causes often encountered in pipe jacking construction are analyzed, and some preventive measures are proposed.
Cement drainage pipe
Common problems and prevention measures in cement pipe jacking construction:
1. The axis deviation of cement jacking pipe is too large
The deviation between the jacking axis of the pipeline and the design axis is too large, which makes the pipeline bend, and even causes the pipe joint damage and interface leakage.
(1) Cause analysis.
① The front resistance of the formation is uneven, resulting in uneven stress on the tool pipe, and leading deviation.
② The back of the pipe jacking is displaced or uneven, causing the resultant line of jacking force to shift.
③ The jack is not synchronized, or the jack has a large difference in jacking force, or the installation accuracy is not enough, resulting in the deviation of the resultant line of jacking force.
(2) Preventive measures.
① Before the construction of cement pipe jacking, the geological conditions of the zone where the pipeline passes through shall be carefully investigated, and the force measuring device shall be set to guide the rectification. Deviation correction shall be carried out according to the operation methods of frequent measurement, frequent correction and small amount correction.
② Use hydraulic jack of the same specification to make its jacking force, stroke and speed consistent, and keep the resultant line of jacking force coincident with the pipeline centerline.
③ Strengthen the control of the construction quality of the back of cement pipe jacking, ensure that the back does not move, and make the back flat to ensure the installation accuracy of jacking equipment.
④ During the jacking process, the jacking curve shall be drawn at any time to guide the jacking correction.