Underground engineering, including tunneling and excavation projects, often cause disturbances to the surrounding rock formations during construction, leading to impacts on nearby buildings and structures. Incidents like the collapse at Shahe Station of Line 11 in Guangzhou on December 1, 2019, resulting in three casualties and direct economic losses of approximately 20.47 million RMB, underscore the urgent need to minimize construction-induced disturbances in the surrounding environment. To achieve this goal, the following aspects need to be studied: ① the mechanisms of strata disturbance during construction, and ② construction disturbance control techniques. Our research team has consistently pursued studies in this direction, accumulating experience and results from model experiments and numerical analyses. Specific achievements include:
(a) Ultra-close-range tunneling: Combining sophisticated finite element analysis with on-site monitoring, the research unveiled disturbance patterns of large-diameter (>14m) shield tunneling within "1-meter range" ultra-close-range tunneling conditions. Through sensitivity analysis, a "framework-type" reinforcement form (MJS) was proposed, successfully controlling the settlement of nearby elevated pile foundations at the "millimeter level."
(b) Special cover soil shield tunneling: Collaborating with Shanghai Tunnel Engineering Co., Ltd., our team pioneered a systematic study on "ground-based shield tunneling-induced ground disturbances." This research explored ground disturbance patterns under "zero cover soil" and "super shallow cover soil" conditions during shield tunneling without working wells. For the first time, it revealed the typical non-uniform convergence distribution pattern of displacements around the excavation area in hard clay conditions, with the lowest point of convergence located 2 cm below the excavation face centroid.
(c) Karst strata construction disturbances: Leveraging deep foundation pit excavation projects at subway shield tunnel working wells and stations in Guangzhou's karst region, our research combined nonlinear finite element simulation with on-site monitoring to examine the impact of MJS reinforcement on the soil disturbances around the foundation pit. In-depth analysis of a major deformation incident near an elevated highway revealed a close relationship between the accident's cause, MJS pile quality, and hydraulic communication brought by karst caves. Through sensitivity analysis, an improved MJS reinforcement scheme was proposed, pushing surface settlement from the "centimeter level" to the "millimeter level."
Students: Mr Shoudong Gao (2017 intake, 2020 graduated), Mr Chen Liao (2017 intake, 2020 graduated)
Collaborator: Assoc. Prof. Yubing Yang (South China Agricultural University)