Experimental Study of Influence of Karst Aquifer on the Law of Water Inrush in Tunnels

Abstract

Water inrush is a geological hazard often encountered in tunnel construction. In order to overcome problems encountered when using the existing water-inrush simulation model test, such as single function, low repetition utilization rate, and poor visibility, we developed a multi-type water-inrush model test system. Our test system can be a precursor to large-scale studies, handle multiple types, and perform serialization and visualization. We conducted cavity water-inrush simulation testing using this device, and studied the failure model of aquifuge rock. We reveal the evolution laws of water inrush from the cavity, including the initiation of fracture in the aquifuge rock, the formation of water-inrush channels, and the rupture of the aquifuge rock. By analyzing the seepage pressure changes at the monitoring points of the aquifuge rock, we divided the water-inrush process of the cave into a rack generation stage, a holing-through of fracture and forming of water-inrush channel stage, and a water-inrush stage. Test results show that the system is stable and reliable, only requiring a short test period, and can be used to guide large water-inrush testing and related projects.

Hydraulic Behavior of Karst Aquifers

“…Intermittent uplifting of regional structures provides hydrodynamic conditions for the development of conduits, causing the hydraulic gradient to be inconsistent, meanwhile, the cut blocks easily lose their stability and provide space for karst development. The authors further considered the effect of the vertical zoning of the fault structure and the excavation disturbance, and, drawing on the experiences from the relative location at the same site in the same field, put forward the suggestion that the construction of the follow-up tunnel in the study area should be slightly higher than the elevation of the underground river [16]. The research results discussed here can provide useful reference for similar engineering problems in the future.…”

“…Constant exchange of best practices, technological progress, and new ideas in this engineering segment, connected with interactions of karstic groundwater and underground constructions, continues also in our Special Issue. Three papers presented here aimed at detailed groundwater monitoring for underground structures in karsts [14], formulation of evolutionary laws on water inrush from the cavity [15], and description of the reverse fault control mechanism in the development of underground rivers [16]. Although these do not cover the entire spectrum of underground engineering problems in karsts, but due to their presence in this Special Issue, they can be considered as new gems in the mosaic of karst geotechnics.…”

“…According to the test results, the multi-type water-inrush model test system was stable and reliable, only requiring a short test period, and can be used to guide large water-inrush testing and related projects. Zhang et al [16] then discuss the traditional idea that the reverse fault is not easily developed for an underground river (conduits), which means that the tunnel elevation design is not considered adequately. Taking the Qiyueshan Tunnel site as an example, on the premise of the anatomy of the control mechanism of the reverse fault on the development of the underground river, based on the multiperiod typical structural traces of the tunnel and surface outcrop, it was found that stratifications, dip joints, transverse joints, and tension joints of good aperture grade should be the important control factors.…”

Spectral Decomposition and a Waveform Cluster to Characterize Strongly Heterogeneous Paleokarst Reservoirs in the Tarim Basin, China

“…The general characteristics of karst systems have been extensively published, and modern cave systems are well-studied [89][90][91][92][93][94][95]. The distribution of fracture-cavity channel systems formed by the action of paleo-karst water can be divided into network, dendritic, pinnate, single-pipe, individual, and other forms [88].…”

A Normal Cloud Model-Based Method for Risk Assessment of Water Inrush and Its Application in a Super-Long Tunnel Constructed by a Tunnel Boring Machine in the Arid Area of Northwest China

“…Water inrush has great perniciousness in tunnel excavation [1,2]; particularly for a tunnel constructed by a tunnel boring machine (TBM), it may not only submerge the mechanical equipment of the TBM, which is worth tens of millions of dollars, but also seriously endanger the safety and life of the builders in the tunnel [3,4]. For the construction of tunnels in arid areas, water inrush also leads to a decline in groundwater level, surface vegetation degradation, and land desertification [5].…”