隧道开挖引起上部建筑物沉降的离心模型试验研究

Centrifugal model tests on settlement of structures caused by tunnel excavation

地下隧道选线时,常不可避免的出现下穿建筑物的情况。为保证上部建筑物的安全稳定性,需要控制下穿隧道引起的建筑物基础的沉降。不同基础型式的建筑物在下穿隧道施工中,沉降变化不同。通过三维离心模型试验,研究了双管大型隧道开挖引起的浅基础办公楼和桩基础厂房的沉降情况。由于隧道开挖引起的应力释放,建筑物基础的实测沉降随隧道的开挖而增加。距离隧道开挖距离近的位置沉降值较大,距离开挖距离远的位置沉降值较小。桩基础厂房的沉降值都明显小于浅基础办公楼。而开挖近点的沉降值大于远点的沉降值,最大可相差2.8倍。开挖初期浅基础的不均匀沉降量明显高于桩基础,最大值可相差6倍。最终隧道开挖完成后,桩基础的不均匀沉降量小于浅基础。

In the construction of underground tunnels,the route selection often inevitably leads to the situation of under-passing buildings.In order to ensure the safety and stability of the superstructures,it is necessary to control the settlement of the building foundation caused by the underpassing tunnel.In the construction of underpassing tunnel,the settlement changes of buildings with different foundation types are different.Through the three-dimensional centrifugal model tests,the settlements of shallow foundation office buildings and pile foundation workshop caused by the excavation of double-tube large tunnel are studied.Due to the stress release caused by tunnel excavation,the measured settlement of building foundation increases with tunnel excavation.The settlement value at the position close to the tunnel excavation is larger,and that at the position far from the excavation is smaller.The settlement value of pile foundation is obviously smaller than that of the shallow foundation buildings.However,the settlement value at the near point of excavation is greater than that at the far point,with a maximum difference of 2.8 times.At the initial stage of excavation,the differential settlement of the shallow foundation is obviously higher than that of the pile foundation,and the maximum value can be 6 times.After the tunnel excavation,the differential settlement of the pile foundation is less than that of the shallow foundation.