Abstract A water-filled cave can easily result in the deterioration of the surrounding rock when a shield tunnel passes through the urban karst area, resulting in engineering disasters such as water inrush, ground collapse, and shield machine malfunction. To study the surrounding rock stability due to the proximity of a cave with confined water, we carried out a large-scale three-dimensional geo-mechanical model test on a tunnel that was excavated by a compound EPB (Earth Pressure Balance) shield machine based on the metro tunnel in the “spring city” of Jinan. We developed a new 3D printing technology for a water-filled cave and a new method for the 3D laser reconstruction of surface settlement monitoring. The multi-physics evolution information, including the soil moisture content of the muck, the displacement, the stress, and the seepage pressure, were obtained and proven consistent with each other. The results showed that the water inrush mainly resulted from a shield tunneling disturbance in conjunction with the confined water in the cave. The process of water inrush in the surrounding rock could be divided into three stages, which included the initial stable period, the variation period with the shield tail passing through, and the final stable period. The rock ahead of the excavation face was characterized by two stages, which included the initial stable period and the sudden collapse of the water-resistant slab. Compared with the tunnel excavated by drilling and with the blasting method, the water inrush triggered by the EPB shield machine tunneling was observed to be more hidden and catastrophic. The displacement and the seepage pressure comprised the most intuitive precursor information. These test results can provide a theoretical basis and guidance for the water inrush prediction for being triggered by a single confined cave with no inter-connections.

中文翻译：

---

邻近充水洞穴盾构隧道突水前兆信息的实验研究

摘要 盾构隧道穿过城市岩溶区时，充水洞室容易造成围岩劣化，引发突水、地面塌陷、盾构机故障等工程灾害。为研究邻近承压水洞穴的围岩稳定性，我们对采用复合EPB（地压平衡）盾构机开挖的隧道进行了大型三维地质力学模型试验。济南“春城”地铁隧道。我们为充满水的洞穴开发了一种新的 3D 打印技术和一种新的地表沉降监测 3D 激光重建方法。多物理场演化信息，包括淤泥的土壤含水量、位移、应力、和渗流压力，得到并证明是一致的。结果表明，突水主要由盾构掘进扰动和洞内承压水共同作用引起。围岩突水过程可分为初始稳定期、盾尾穿越变化期和最终稳定期三个阶段。开挖面前方的岩石具有初始稳定期和防水板突然坍塌两个阶段的特征。与钻孔和爆破法开挖的隧道相比，EPB盾构机掘进引发的突水更隐蔽、更具灾难性。位移和渗流压力是最直观的前兆信息。这些试验结果可为单一承压溶洞、互不连通引发的突水预测提供理论依据和指导。