Micro pipe jacking process

Micro-Pipe Jacking Process

Micro-Pipe Jacking is often excavated using the ground-rope method. The ground-rope method is divided into standard ground-rope and modified ground-rope, depending on whether soil is removed or not. The standard ground-rope method involves soil removal, while the modified ground-rope method involves compaction and advancement without soil removal. The ground-rope method utilizes a hydraulic device with a guide tube as a conductor, connected to a spiral excavation tube and a reaming cutting head at its end. The pipe to be laid is then connected behind the guide tube, and the pipe is pushed forward according to the designed trajectory to complete the laying of the new pipeline.

Applicable Conditions

Micro-Pipe Jacking is an emerging trenchless construction technology suitable for areas with small construction sites, complex surrounding environments, and complex underground pipelines. Deep buried, gravity-flow drainage pipes are preferred for jacking. It can be used in soft soils such as sandy and clayey soils. According to relevant domestic and international experience, the distance between each section should not exceed 80m, and the maximum working pit depth should not exceed 15m. This process is suitable for small-diameter pipelines with a diameter of 600mm or less.

Process

The modified ground-arrow micro-pipe jacking construction process is as follows: On-site alignment survey - Working well construction - Backrest installation - Machine erection, laser theodolite installation and commissioning - Hole drilling and water-stop installation - Arrow and pilot pipe jacking - Black pipe jacking - Installation of a simple extrusion and expansion machine head - Resin concrete pipe jacking - Machine head and micro-pipe jacking equipment removal - Inspection well construction - Steel casing removal and backfilling - CCTV inspection.

Precautions for the modified ground-arrow method

When using the modified ground-arrow method, if the pipe diameter is too large, the cover depth is too small, or excessive soil is squeezed, ground heave may result. If the soil is dense, the volume that can be squeezed is limited, causing ground heave. If the soil is too strong or contains gravel, the method cannot penetrate. If the soil density is uneven, the soil will squeeze in the softer direction, resulting in poor jacking alignment accuracy. Therefore, the pipe diameter, cover depth, and soil properties should be considered and applied appropriately. In short, this technology has many advantages such as small footprint, convenient construction, short construction period, low project cost, small impact on ground traffic, small impact on the surrounding environment and existing pipelines, and high pipeline laying accuracy. It will have broad application prospects in small-diameter drainage pipeline projects.