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| The Effect of Pressure Release of Gaseous Phase and Pressure Released Gather Underground Water of Gaseous Phase in Vadose Zone When Tunneling |
| XU Zeng-rong |
| (China Railway First Survey and Design Institute Group Co. Ltd, Xi′an, Shaanxi 710043, China) |
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Abstract Abstract：Research purposes： The people be nagged by cause of tunnel leakage and little water burst in vadose zone in long times during tunnel construction or operation. This paper finds out the main factor that affect moisture change of tunnel periphery through analysis of three phase changing of soil after excavation, reveals the cause of tunnel leakage and the formation of saturated zone, reasonably explains the question of tunnel leakage that tunnel located in the underground water level and no perched water, and puts forward new concept about gaseous phase migration and part underground water around tunnel. Research conclusions： (1)The pressure increase grads of gaseous phase in vadose zone are greater than the pressure increase grads of atmosphere in about most mouths of one year. (2)After excavation of the tunnel, converging movement of gaseous phase in vadose zone appears, and moisture of gaseous phase generates movement, adsorption, conversion, this phenomenon is named as the effect of pressure release of gaseous phase in vadose zone in this paper. This paper thinks that this effect is another important influence except the surrounding rock change of stress field when tunneling. Partial saturated underwater in surrounding rock produced by the effect of pressure release of gaseous phase is named pressure released gather underwater of gaseous phase in vadose zone, this underground water overflowing is main reason of tunnel leakage and little water burst in vadose zone. (3)This paper can be used for the survey of engineering geology and hydrogeology in tunnel engineering and other underground engineering.
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Received: 19 October 2017
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2017, Vol. 34 
