An evaluation of fine grained sedimentary materials in terms of geotechnical parameters which define and control excavation performance of EPB TBM’s

An assessment method for fine‐grained sedimentary materials excavated by EPB TBM

“…A number of laboratory and in-situ tests have been performed on the soil samples, which were obtained from the tunnel route between 1261 and 2186 m [20]. The measurements and evaluation of the excavation performance of EPB TBM was discussed under the two main data sets of the integrated parameter.…”

“…To accurately define various physical properties of soil, 14 different soil samples were collected from the grout holes of the segmental lining at seven different points (1,285, 1,350, 1,580, 1,680, 1,740, 1,820, and 1,934 m) of tunnel alignment by a hand drill (∅ = 30 mm; Table 1) [20].…”

“…- Table 1. Measurements of the geotechnical and real-time EPBM performance parameters in the tunnel sampling site [20] The samples were classified under "clayey" material, and because the samples ranked within a 15 ≤ PI ≤ 40 limit range, they were classified as "middle (CI) and high (CH)" and "extremely high (CV)" plasticity soil (see Figure 3a). -When the tunnel route was investigated in relation to the lumping potential, a "high risk of lump formation" was observed (see Figure 3b).…”

“…The excavation procedures were performed in open mode (no counter pressure applied to the face) at a constant [20] value of rotation per minute (rpm) of 2.8. Figure 4 provides a brief summary.…”

“…In tunneling literature, most research is focused on advance rate prediction of the hard-rock TBMs, but limited studies have examined the excavation performance of EPB-TBMs. More recently, a new empirical equation has been used to evaluate EPBM performance parameters on soft ground conditions [20,21].…”