高速铁路路基分布式光纤沉降监测与控制研究

The high-speed railway subgrade is the foundation to bear the track weight and train load, so its service state directly influences the driving comfort and safety. In order to solve the hot issues on the subgrade settlement monitoring and control for high-speed railway, this research is launched on the basis of combination of the advantages of the long-distance measurement of the distributed optical sensor and the high strength of the geotextile. Firstly, a distributed optical fiber settlement monitoring sensor is to be designed which can identify the subgrade deformation direction. Consequently, the signal process and analysis method for the strain-settlement sensing data will be studied. Then the distributed optical fiber sensor and the high-strength geotextile will be combined to develop a high-strength intelligent geotextile, and based on which the settlement monitoring and control method will be experimental and theoretical studied. Finally, a full scale subgrade model is to be established for the conduction of the corresponding subgrade settlement monitoring and control tests. The settlement evaluation method for the high-speed railway subgrade will be studied based on the settlement data measured by the distributed optical fiber settlement monitoring sensor and the geotextile deformation. This project will provide a sound system of settlement monitoring and control, and safety assessment for high-speed railway subgrade, which is not only significant for the driving comfort and safety of high-speed railway, and also of great engineering application value.

高速铁路路基是承受轨道结构重量和列车荷载的基础，其服役状态的好坏直接影响高速列车行车平顺性和安全性。本项目针对高速铁路路基沉降监测和控制热点问题，结合分布式光纤传感长距离测量和土工布高抗拉强度优点，开展高速铁路路基沉降监测与控制技术研究。首先研发可识别路基变形方向的分布式光纤路基沉降监测传感器及开展应变-沉降传感信号分析处理方法研究；然后将分布式传感光纤与高强土工布复合，研发分布式光纤高强智能土工布，研究基于分布式光纤高强智能土工布加固的路基沉降监控方法；最后建立高速铁路路基足尺模型，开展路基沉降与控制试验研究，融合分布式光纤沉降监测信息和分布式光纤高强智能土工布变形信息，研究高速铁路路基长期服役沉降监控评估方法。本项目的完成将为高速铁路路基提供一套沉降监控和安全评估系统，对保障高速铁路行车的平顺性和安全性具有重要研究意义和工程应用价值。

我国高速铁路网规模质量大幅提升，有力支撑了国家重大战略。截止2022年底，高铁运营里程达到4.2万公里，稳居世界第一。高速铁路穿越地质条件复杂，在岩溶发育区、煤矿采空区、软土区域及其他不稳定地质区域，路基存在不均匀沉降和突发塌陷风险。高速铁路路基是承受轨道结构重量和列车荷载的基础，其服役状态的好坏直接影响高速列车行车平顺性和安全性。本项目针对高速铁路路基沉降监测和控制热点问题，结合光纤传感和土工布高抗拉强度优点，开展高速铁路路基沉降监测与控制技术研究。首先，研发了可识别路基变形方向，纤维增强树脂封装的光纤传感器、匹配不同模量路基监测的线缆式光纤光栅应变传感器以及可用于不同变形方向监测的光纤光栅平面姿态监测传感器三种满足不同路基监测需求的传感器；其次为有效获取路基沉降量，提出了应变累积积分的应变-沉降关系模型、光纤布里渊频移-沉降拟合关系模型以及基于高强度智能土工布加固的岩溶塌陷沉降计算模型；再次，研发小直径光纤传感器和光纤智能土工布以及适合土工布大变形测量的基于同轴电磁波F-P干涉技术的智能土工布（变形量程可达15%以上），并通过室内研究了智能土工布测量变形的有效性；然后，构建足尺模型试验，基于智能土工布监控特点，开展路基扩展监测，同时构建小尺度室内路基模型，基于分布式光纤传感器有效监测了不同尺度下的土洞塌陷；最后结合分布式光纤振动、应变以及智能土工布构建了一套高速铁路路基沉降监测与控制系统，提出了集分布式光纤振动-应变一体化的高速铁路路基岩溶土洞全过程监测方法，基于上述研究成果，在安六高铁、玉墨线、贵南高铁建立基于光纤传感的路基沉降监测示范系统，监测数据为路基施工和运营提供了有效的监测数据，提升了铁路运营安全。