The Weihe Tunnel on Baoji-Lanzhou Passenger-dedicated Line passes through the Neogene mudstone for a long distance in Tianshui,Gansu. The strength and stability of rock are poor and the infiltration of the river has great influence on the construction and operation of the tunnel. In order to put forward reasonable tunnel construction countermeasures, the compressive strength, compression deformation, expansibility, disintegration and water permeability of the Neogene mudstone in Tianshui,Gansu are carried out by laboratory tests. The results show that:1) The Neogene mudstone is extremely soft, which is not expansibile but is with disintegration after water absorption. 2) The infiltration coefficient of the Neogene mudstone is very small,which belongs to the micropermeable stratum,and the water separation effect is good. During the tunnel construction, non-blasting excavation methods are recommended and the formation displacement is strictly controlled. The principle of strong support and early closure should be followed and the surrounding rock should not be soaked by construction water.%宝(鸡)兰(州)客运专线渭河隧道在甘肃天水地区藉河河谷区长距离穿越新近系泥岩,岩层强度低、稳定性差,且河水下渗对隧道的施工和运营影响极大.为提出合理的隧道施工对策,采用室内试验方法,针对甘肃天水地区新近系泥岩的抗压强度、压缩变形、膨胀性、崩解性以及渗透性开展全面试验.试验结果表明:1)新近系泥岩属于极软岩,不具有膨胀性,但吸水后显现出一定的崩解性;2)新近系泥岩渗透系数很小,属于微透水岩层,隔水效果较好.隧道施工过程中建议采用非爆破的方法进行开挖并严格控制地层位移,遵循"强支护、早封闭"的原则,尽量避免施工用水浸泡围岩.
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