To investigate the
mechanisms of water and mud inrush and roof collapse when tunneling through
water-rich tertiary semi-diagenetic strata, a case study is conducted on Wangjiazhai tunnel
of the Linze-Qingshui highway in Yunnan, China, and the
mechanical properties, action mechanisms, and water inrush risk of tertiary
semi-diagenetic strata are examined through indoor
mechanical tests and fuzzy analytic hierarchy process. The results reveal the
following: (1) The tertiary semi-diagenetic strata in
the Wangjiazhai tunnel significantly soften upon water exposure, with cohesion
initially increasing and then decreasing as water content rises, while the
internal friction angle continuously decreases. At 18% water content, cohesion
and internal friction angle are 12.53 kPa and 7.53°,
respectively, indicating rock mass destabilization. (2) Weak tertiary semi-diagenetic strata, high groundwater level, and tunnel excavation
disturbance are the primary factors influencing water and mud inrush disasters
in the Wangjiazhai tunnel. (3) The tertiary semi-diagenetic
strata section of the tunnel can be divided into four parts (A, B, C, and D)
based on engineering geological and hydrogeological conditions, with disaster
risks ranked as B=C>A>D. The estimated mud inrush volume in section A
closely matches the actual disaster situation.
LIU Chengwen, LIU Gang, XU Hua, DING Guopeng
. Mechanism and Risk
Assessment of Water and Mud Inrush in Water-Rich
Section With Tertiary Semi-Diagenetic
Sandstone and Mudstone in Wangjiazhai Tunnel[J]. Tunnel Construction, 2024
, 44(S1)
: 139
-148
.
DOI: 10.3973/j.issn.2096-4498.2024.S1.015
