基于应变测量的隧道周边水土压力反演方法研究

Inversion Method of Surrounding Water-Earth Pressure of Tunnel with Strain Measurement

周边水土压力变化是影响隧道结构安全的重要指标,但既有监测方法难以实现周边水土压力的长期准确测量.鉴于此,提出了一种基于应变测量的隧道周边水土压力反演方法.首先介绍了隧道周边水土压力的简化模型,并基于最小二乘法建立了应变-压力的反演矩阵;然后通过预埋光纤光栅传感器测量隧道结构断面的应变分布,并通过应变-压力之间的关系来反演隧道周边水土压力;最后分别通过有限元模型和隧道工程现场监测试验证明了反演的隧道周边水土压力的精度可满足工程需求.由于光纤光栅传感器在长期监测隧道结构断面的应变分布时具有的优良性能,因此通过应变-压力之间的关系反演隧道周边水土压力的方法可用于隧道周边水土压力的长期监测.

The change of surrounding water-earth pressure is an important index affecting the safety of tunnel structure,but the existing monitoring methods are difficult to achieve long-term accurate measurement of surrounding water-earth pressure.In view of this,this paper proposes an inversion method of water-earth pressure around tunnel based on strain measurement.Firstly,the simplified model of water-earth pressure around the tunnel is introduced,and the strain-pressure inversion matrix is established based on the least square method.Then the strain distribution of tunnel structure section is measured by embedded fiber bragg grating sensor,and the water-earth pressure around the tunnel is inverted by the relationship between strain and pressure.Finally,the accuracy of the inverted water-earth pressure around the tunnel can meet the engineering requirements,which is proved by finite element model and tunnel engineering field monitoring test respectively.Because of the excellent performance of fiber bragg grating sensor in long-term monitoring of strain distribution of tunnel structure section,the inversion method of water-earth pressure around tunnel through strain-pressure relationship can be used for long-term monitoring of water-earth pressure around tunnel.