铁路隧道基底破坏力学形态的试验研究

针对既有铁路隧道底部病害严重的现状，采用模型试验方法对该问题进行了研究。试验中主要对不同隧道铺底工况进行疲劳试验，以了解不同铺底工况疲劳裂纹的出现时间、扩展情况以及使用寿命等，同时对作用于铺底结构上的压应力及弯应力也进行了测试。试验结果表明，在机车轴重荷载作用下，作用于隧道铺底结构顶面的竖向压应力基本在0．2MPa以内，而铺底底面的弯拉应力一般在0．8MPa以上，铺底结构属于受弯破坏；另外，通过试验得到了20cm厚钢筋混凝土的隧道基底结构更优的结论。在试验成果的基础上，对隧道铺底结构的受力状态及其计算方法进行了探讨。

An Experimental Study on Mechanics Pattern of Bed Disease in Railway Tunnel

In view of the severe situation about the bed disease in the existed railway tunnel, the model experimental method is used to study the problem. Fatigue tests were performed on the different tunnel bed modes in order to know the emerge time and the expansion condition of fatigue cracks and the service life of them. And the compressive stress and bending stress on the tunnel bed were also tested. The experimental results show that the tunnel bed is destroyed by bending stress when the compressive stress acting on tunnel bed is less than 0.2 MPa and the bending stress in it is generally larger than 0.8 MPa under the axial load of locomotive, the tunnel bed is destroyed because the bending stress is circularly acted on and it is large. A conclusion also can be drawn that the tunnel bed construction can be optimized if it is made of 20 cm-thick reinforced concrete. Based on the experimental results, the mechanics pattern of tunnel bed construction is analyzed at the end.