泥石流两相介质体作用下的石块冲击力计算与测量方法

Boulder within debris flow (DF) is the key factor contributing to the peak impacting force of DF. It is also the key reference factor to the design of DF control engineering and the health monitoring during engineering operation. However, attributing to the constrain of flume test method and conventional piezoelectric sensors, the measured impacting force is not adequate to reflect the real level of impacting force of debris flow, and this situation renders that the theory model of boulder impact force cannot be tested. To solve this issue, this project intends to design a new measuring device by integrating Fiber Bragg Grating (FBG) to steel-back reinforced concrete composite beam. In this new device, FBG will be certain-spacing-interval fixed on the steel bar that sustains the longitudinal stress in the composite beam, so FBG can be used to monitor the strain of steel bar; the composite beam plays the function of contacting the DF and protecting the sensors. Taking this new device as the impact carrier, the drop tests will be designed in order to simulate the real impact force of natural DF. The corresponding rule of peak value of steel bar’s dynamic strain to the external impacting force will be analyzed, and the calculating model will be established and verified based mechanical theory. The flume experiments will be also designed for analysis of the two-phase DF impacting force signal, and based on the signal analysis, the strain information of steel bar just induced by the boulder within the DF will be extracted, which then can be inputted into the calculating model and finally the boulder impact force within two-phase DF will be determined using the new designed measuring device.

泥石流中的石块是造成泥石流冲击力峰值的关键因素，也是防治工程设计和工程后期运行时健康监测的关键参考因子。但是目前受到水槽试验方法和常规传感器的限制，泥石流冲击力的测量数据可靠性低，且无法体现石块的冲击力水平，石块冲击力的理论计算模型无法通过试验校验。鉴于此，本项目拟采用光纤布拉格光栅(FBG)与钢板-钢筋混凝土组合梁相结合的方式，设计一种新的泥石流冲击力测量装置：在组合梁纵向受力钢筋上按一定间距布置FBG，利用FBG监测钢筋的应变，组合梁与外部泥石流接触，并保护光纤传感器；以测量系统为基础，建立悬臂梁冲击力计算模型和设计冲击力试验方案，利用冲击力试验数据校验和修正悬臂梁冲击力计算模型；利用水槽试验分析泥石流两相体的冲击特性，从连续的泥石流冲击信号中，提取石块冲击诱发的钢筋应变信息，为计算模型提供输入参量，实现浆体-石块两相介质作用下的石块冲击力计算与测量方法。

泥石流中的石块是造成泥石流冲击力峰值的关键因素，也是防治工程设计和工程后期运行时健康监测的关键参考因子。但是目前受到水槽试验方法和常规传感器的限制，泥石流冲击力的测量数据可靠性低，且无法体现石块的冲击力水平，石块冲击力的理论计算模型无法通过试验校验。鉴于此，本项目采用光纤布拉格光栅(FBG)与钢板-钢筋混凝土组合梁相结合的方式，设计了一种新的泥石流冲击力测量装置：在组合梁纵向受力钢筋上按一定间距布置FBG，利用FBG监测钢筋的应变，组合梁与外部泥石流接触，并保护光纤传感器；以测量系统为基础，建立了悬臂梁冲击力计算模型和设计冲击力试验方案，利用冲击力试验数据校验和修正了悬臂梁冲击力计算模型；利用水槽试验分析泥石流两相体的冲击特性，从连续的泥石流冲击信号中，提取石块冲击诱发的钢筋应变信息，为计算模型提供输入参量，实现了浆体-石块两相介质作用下的石块冲击力计算与测量方法。