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Annotated Dictionary of Construction Safety and Health
Published in Charles D. Reese, James V. Edison, Annotated Dictionary of Construction Safety and Health, 2018
Charles D. Reese, James V. Edison
Employees are not to work in excavations in which there is accumulated water, or in excavations in which water is accumulating, unless adequate precautions have been taken to protect employees against the hazards posed by water accumulation. The precautions necessary to adequately protect employees vary with each situation, but could include special support or shield systems to protect from cave-ins, water removal to control the level of accumulating water, or the use of a safety harness and lifeline.
Risk assessment of water inrush caused by karst cave in tunnels based on reliability and GA-BP neural network
Published in Geomatics, Natural Hazards and Risk, 2020
Zhaoyang Li, Yingchao Wang, C. Guney Olgun, Shengqi Yang, Qinglei Jiao, Mitian Wang
Where, hs is the distance between the tunnel and karst cave. h1 is the thickness of karst fracture zone. Both are determined by geophysical prospecting or drilling. h2 is the effective against-inrush thickness, which needs to be determined by further calculation. h3 is the influence thickness under blasting disturbance and excavation unloading, which is generally 1.5 m based on experience (Meng et al. 2020). When hs is equal to the sum of h1, h2 and h3, the rock strata between tunnel and cave is in a critical state, as shown in Figure 1. According to the comparison between the sum of h1, h2, h3 and hs, whether water inrush occurs can be judged. When hs is larger, the rock strata can effectively prevent water inrush. When the sum of h1, h2 and h3 is larger, water inrush disaster will occur. Among them, h1 and h3 represent the thickness of the rock strata that cannot effectively resist water inrush.
Saving and conserving the caves: reflections on 37 years of listings, disputes, submissions and court cases
Published in Australian Journal of Earth Sciences, 2019
The third problem with conservation by secrecy is unintentional damage where the location and significance are not available to decision makers. Other risks include subdivision, which may make the site unmanageable, or inappropriate activities on adjacent land. As well as posing a risk to the cave, unmapped karst features can be a risk if buildings are constructed on land vulnerable to karst processes such as sinkhole failure. This is not hypothetical, as one speleological society has refused to share information with a council that manages a town built on karst that is vulnerable to sinkhole failure or “secret” caves could be filled with sewage sludge from biosolid disposal.
Analysis on the safe distance between shield tunnel through sand stratum and underlying karst cave
Published in Geosystem Engineering, 2019
Wei Wang, Shiming Gao, Lingfeng Liu, Wushuang Wen, Ping Li, Jianping Chen
If the roof of karst cave is destroyed by the external force, the sand can directly enter the karst caves developed in the limestone. With large leakage of sand, a conical collapse pit can be formed in the ground, which will directly or indirectly affect the safety of subway tunnel. The horizontal distance from the karst cave boundary to the tunnel border determines the influence degree of the karst collapse on the tunnel structure.