隧道围岩渗流和衬砌水压力荷载

从地下水的渗流作用出发，对作用于隧道衬砌的水压力荷载的计算进行了讨论，并得出以下几个结论：一是在采用全封堵防水衬砌的情况下，无论围岩的渗透系数多小，都必须考虑同地下水位相应的水压力荷载。二是只有透水的衬砌（或设置排导系统）才能考虑水压力折减系数。水压力折减系数的量值主要取决于衬砌渗透系数同地层渗透系数之比。三是对于高水头的深埋隧道，为避免量值较大的水压力，应设置排导系统，不宜采用全封堵衬砌结构。要采用围岩注浆来控制地下水的排放流量。

Problems on External Water Pressure on Tunnel Lining

On the basis of seepage analysis, some problems on external water pressure on lining of tunnels are discussed in this paper. The emphases are especially given to：
（ 1 ） When full-sealing water proofing lining is employed, no reduction coefficient for the water pressure should be considered into account no matter how small the permeability coefficient of the ground is.
（2） For the permeable lining（ drainage approach） , a reduction coefficient which is determined by the ratio of permeability coefficient of lining to that of ground rock may be taken into account, i. e β =f（ kl/kr）,
（3） In order to avoid high water pressure, for deep tunnels with high water head of ground water, a drainage system may be recommended instead of full-sealing water proofing lining. In that case, ground grouting is a proper measure to control the loss of ground water and benefits zoology conservation.