Micro-vibration parameters fast demodulation algorithm and experiment of self-mixing interference

Self-mixing interference （SMI） technique can be used for measuring vibration, displacement, velocity and absolute distance. In this paper, a simple demodulation algorithm for fast measuring frequency and amplitude of a simple harmonic vibration target is proposed based on the basic theoretical model of self-mixing interference effects. The simulative results show that the error between the vibration parameters which are demodulated by this algorithm and initial settings merely results from the sample rate. Further, the experimental system of self-mixing vibration measurement is built. The experimental results have a good agreement with simulation analyses. The maximum error of frequency demodulation is less than 1 Hz in our experiment.     

锚杆作用下块状岩体力学特性试验研究

以巷道围岩的一个单元为研究对象,通过研制成套的相似材料和加载模具,对边长200 mm的立方体试样进行压缩试验,研究块体尺寸和锚固方式对块状岩体力学行为的影响。试验结果表明:块体尺寸越大,锚杆与岩体的黏结性能越强,可以更好地发挥锚杆的支护作用,随着层理面间距的增大,岩体峰值强度和弹性模量均呈现逐渐增大的趋势;与端锚相比,加长锚和全锚更能提高锚杆与破裂岩体的黏结能力,抑制脱锚现象的发生,增加支护效果,随着锚固长度的增大,岩体峰值强度和弹性模量均逐渐增大。研究成果可为煤矿巷道破裂围岩的锚杆支护设计和失稳破坏预警预测提供理论依据。     

路基粉土动态回弹模量试验与预估模型研究

对不同含水率和压实度下的路基粉土进行动态回弹模量试验,结果表明：动态回弹模量随着围压的增大而增大,随着偏应力的增加而减小,其受围压的影响更为显著;随着含水率的增大而减小,随着压实度的增大而增大,受含水率的影响更为显著。最后采用物性指标参数塑性指数、含水率、压实度和力学指标参数CBR指标,建立路基粉土动态回弹模量预估模型。