高速铁路泥岩地基膨胀变形试验及渗透试验研究

Study on Expansion Deformation Test and Permeability Test of Mudstone Foundation of High-speed Railway

为研究水在不同渗流方向下对高速铁路无砟轨道泥岩地基膨胀性及渗透性的影响规律,以兰新高铁DK1345+200里程为试验点,借助自主研发的测试仪器,进行在不同上覆荷载下膨胀变形及水平、竖向渗流原位试验。结果表明:不同荷载下泥岩膨胀量随注水时间的变化呈"S"形分布;泥岩膨胀受上覆荷载的约束作用,荷载越大,泥岩膨胀受到的约束作用就越强,膨胀量就越小,反之越大;不同位置处土样的水平及竖向体积含水率均经历缓慢增长、骤然增长和基本稳定3个阶段;在同一位置,荷载越大,土体越密实,体积含水率越小,渗透性越弱。建立荷载与膨胀量计算模型,实测数据与模型计算结果吻合度较高。

In order to study the influence of water on the swelling and permeability of mudstone foundations of high-speed railway ballastless tracks in different seepage directions,DK1345+200 mileage of the Lanzhou-Urumqi high-speed railway is used as a test point,and independently developed test equipment is employed to perform in-situ tests of swelling deformation and horizontal and vertical seepage under different overburden loads.The results show that the expansion of the mudstone under different loads shows an“S”distribution with the change of water injection time;the expansion of the mudstone is constrained by the overlying load.The larger the load,the stronger the constraint of the expansion of the mudstone and the smaller the expansion,and vice versa.The horizontal and vertical volumetric water content of the soil samples at different locations undergo three stages of slow growth,sudden growth,and basic stability.At the same location,the larger the load,the denser the soil,and the smaller the volumetric water content,the weaker the permeability.A calculation model of load and expansion is established,and the measured data coincide well with the model calculation results.