地下水开采对桥梁结构影响的离心模型试验研究

Centrifuge modeling of response of bridge due to exploiting groundwater

地下水开采是导致地面不均匀沉降的重要因素之一,而地面不均匀沉降又会对桥梁结构造成较大的危害。通过离心模型试验研究了离心场中地基抽水对桥梁结构物的影响。在自主研制的离心场中地基抽水对结构物影响的模拟和测量系统基础上,测量了抽水过程中粉土地基中沉降的变化以及桥梁结构的变形分布规律,探讨了地面不均匀沉降对刚性桥梁、简支桥梁以及简支连续桥梁的影响规律。试验结果表明,水井抽水的初期非稳定渗流期是桥梁变形发展最快的阶段;减小桥垮长度以及桥面桥墩改用铰连接都可以使得桥面轴向应变减小;地基的水平位移会给刚性桥梁中部带来较大的变形。

Exploiting groundwater is a main reason to the ground settlement and uneven settlement can do great harm to the high-speed railway bridge.Centrifuge model tests are conducted to investigate the influence of exploiting groudwater on the high-speed railway bridge.The deformation of soils and the bridge are measured during the centrifuge model tests of exploiting water based on a drainage system developed to simulate exploiting water during centrifuge tests.The influences of uneven ground settlements on the rigid bridge,simply supporfed single bridge and simply supported multispan bridge are discussed.The results show that the bridge deforms intensively during the period of unsteady fluid flow after water was exploited initially.The axial strain of the deck can be decreased by reducing the length of the balk or replacing the bridge pier by hinged bearing.The horizontal displacement of ground can cause some deformation on the central part of the rigid bridge.