Risk Management For The Construction Through Zones Of Weathered Rock Of Extremely Poor Quality In Xiang'an Tunnel

Xiang'an Tunnel is the first subsea tunnel in our country. The geological condition of Xiang'an Tunnel is so highly intricate that the construction has large risk. Both ends of the three tunnels, the two driving tunnels and the service tunnel, must pass through zones of weathered rock of extremely poor quality before entering into solid rock on-land before entering the subsea section. The construction through zones of weathered rock of extremely poor quality is highly hard. So the risk management research for the construction through zones of weathered rock of extremely poor quality is significative.The geological condition, main construction measure of zones of weathered rock of extremely poor quality is introduced. The paper discusses the risk mechanism of the construction. The whole risk management process is studied in the thesis, with five processes: risk identification, risk estimation, risk assessment, risk control, risk supervision.The main risk factors of construction through zones of weathered rock of extremely poor quality are identificated with WBS and expert investigation method. The construction risk assessment index system is established by the Analytic Hierarchy progress method(AHP).Considering the fuzzy in risk estimation, the thesis resolves the the quantification issue by fuzzy theory. Basing on R=PxC Model, which both considers the collective effect of risk factor probability and loss, the thesis ascertains the risk level of essential factor. Risk level of each step is ascertained by fuzzy synthetic evaluation method. Combining risk control methods, the thesis advances measures through zones of all-or-highly weathered rock. Finally, the paper suggestes four methods for risk supervision.