基于超声波的机制骨料用隧道洞渣母岩抗压强度快速评价方法OA北大核心

To rapidly explore the feasibility of ultrasonic evaluation of the compressive strength of tunnel slag used for manufactured aggregates,the ultrasonic velocity and frequency domain signal characteristics of tunnel slag mother rocks consisting of metamorphic,sedimentary,and igneous rock are examined.An advanced predictive model for the compressive strength of tunnel slag mother rocks based on ultrasonic wave velocity is developed by analyzing the effect of rock type,water content,and specimen size on ultrasonic wave velocity.The results show that ultrasonic signal parameters of tunnel slag mother rocks can accurately indicate the compressive strength of the rocks.The saturated uniaxial compressive strength of the mother rock correlates positively with its ultrasonic wave velocity,regardless of specimen size.The frequency domain signal and main frequency amplitude can reveal internal defects in the rocks with the presence of more pores suggested by a dispersed frequency domain distribution and low main frequency amplitude.The characteristics of the ultrasonic signal spectrum are notably influenced by lithology and mineral composition,with metal minerals exhibiting reduced frequency domain decrease and faster wave speed.The impact of specimen moisture content on mother rock compressive strength is reflected in the speed of ultrasonic waves.The compressive strength for the same tunnel slag mother rocks is as follows:dry state>natural state>saturated state.An evaluation model for saturated compressive strength of tunnel slag mother rocks,based on the classification of metamorphic,sedimentary and igneous rocks,is established.Metamorphic and magmatic rocks showe a linear relationship between ultrasonic wave velocity and uniaxial compressive strength,while sedimentary rocks show an exponential relationship.Practical engineering verification confirms a strong correlation between wave velocity and saturated compressive strength,validating the credibility of the evaluation model.