Measures commonly taken for base treatment in pipe jacking construction

Causes of pipeline instability:

(1) Influence of geological conditions. From the analysis of the instability principle, it can be seen that the bearing capacity and earth pressure of the soil around the pipeline are crucial to pipeline construction, because axis deviation will inevitably occur during the jacking process. If the soil around the pipeline can provide a large reaction force, the pipeline will not be prone to large deviations and instability; if the surrounding soil is weak or uneven, the pipeline will easily become unstable due to insufficient bearing capacity of the surrounding balanced lateral components. At the same time, if the covering layer above the pipeline is too thin, it is easy to cause instability due to insufficient pressure at the top of the pipe. Common phenomena include upward bending of the pipeline axis and bulging in the middle of the pipeline.

(2) Impact on construction quality. According to the cyclic relationship between the curvature of the pipeline and the lateral force component, it can be known that if the offset increases due to untimely or inadequate correction during pipe jacking construction, the pipeline will become unstable, which will have a considerable impact on the construction progress.

(3) Reasons for pipe jacking equipment. During the jacking process, if the connection between the pipe jacking equipment and the pipe is unstable or the rigidity is insufficient, it may cause pipeline instability.

Corrective action.

(1) Improve geological conditions and create favorable conditions for pipe jacking construction. Common measures for base treatment in pipe jacking construction include: using advanced drilling or advanced geological forecasting to determine the geological conditions ahead, and taking pre-reinforcement measures for poor geological sections. In areas with too low bearing capacity, areas with uneven soft and hard soil, areas with too thin covering layers, or areas with buildings on the ground that put pressure on pipeline construction, pre-grouting, anchor rods, pipe sheds, etc. can be used for reinforcement to create stable and uniform geological conditions for pipe jacking construction.

(2) Strictly control the construction quality and improve the pipeline correction effect. Pipe axis deviation is one of the important causes of pipeline instability. Therefore, during construction, control of pipeline axis deviation should be the core content of pipe jacking technology, and axis deviation should be minimized. At the same time, when the pipeline axis deviates, the relevant principles of pipeline deviation correction should be carefully implemented and the deviation should be corrected as soon as possible. At the same time, pay attention to the inspection of pipe jacking equipment and strengthen the pipe connection stiffness.