Slurry Discharge Pipeline Damage and Wear Due to Transporting Rock Particles during Slurry Shield Tunneling: A Case Study Based on In Situ Observed Results

Abstract

Rock particles in excavated materials can damage and wear down slurry discharge pipelines when slurry shield tunneling occurs in a pebble layer and rock ground. This pipeline damage and wear, if not properly dealt with, can lead to a broken-down tunneling machine. Based on a slurry shield tunneling project in China, damage and wear were thoroughly examined. The observed pipeline wear and leaks, transported rock particles, mechanical properties, and flow rate of the carrier slurry were presented. The measured results showed that the wear rates of a straight pipe, a pipe along a curved tunnel, a 60° inclined pipe, and a 90° elbow pipe in pebble ground were approximately 0.71 mm/100 rings, 1 mm/100 rings, 2.14 mm/100 rings, and 4 mm/100 rings, respectively. When the machine drove into rock ground, the wear rates increased by one to two times, which could be attributed to the sharper particle shapes. Countermeasures to address these issues, such as adjusting the pipeline layout, welding reinforcement plates in advance, and preparing additional pipes, were highlighted. The wear rates of different types of pipes, the effectiveness of new pipeline fixing methods, and the probability of pipeline leaks in different strata were discussed in detail.

A Phenomenological Model for Estimating the Wear of Horizontally Straight Slurry Discharge Pipes: A Case Study

“…Finally, the values of the slurry funnel viscosity and specific gravity fluctuated at 20 s and 1.15, respectively. More details about the project can be found in the study by Li et al [36]. The slurry circulation system consists of pipes (Q235B mild steel) with an outer diameter of 300 mm and a wall thickness of 25 mm, elbows, centrifugal pumps, pipe joints, and gate valves, as described in Figure 2.…”

“…Finally, the values of the slurry funnel viscosity and specific gravity fluctuated at 20 s and 1.15, respectively. More details about the project can be found in the study by Li et al [36]. Large rock/pebble particles in the pipe make it difficult to achieve complete suspension under the action of its own gravity, and sliding, rolling, or fluctuations in the pipe inevitably result in the wear of the pipe and even in the slurry gushing during shield tunneling.…”