| Because compaction degree used to evaluate the quality of giant grain of soil subgrade has many deficiencies,the paper relying on chongqing torch-plan projects,"research on mountain giant grain of soil subgrade quality evaluation and test methods based on the uneven settlement control",refering to related research achievements and advanced methods and techniques at home and abroad,the theoretical analysis,laboratory test,engineering application,etc.used to study the relationship between Rayleigh shear wave speed and dynamic resilience modulus in giant grain of soil subgrade.The dynamic resilience modulus is used to detecte and evaluate the subgrade with giant grain of soil.Firstly,this paper introduces the theoretical basis of Rayleigh wave detection,then analyzes in-version methods and influence factors of Rayleigh wave dispersion curves.It solves the problem of the high-frequency effective digital loss to use improved Schwab-Knopoff. The variable parameter and constantly depth niche genetic algorithm used to inverse Rayleigh shear wave speed can shorten the analysis time and improve the analysis accuracy.Secondly,based on the close correlation between Rayleigh shear wave speed and dynamic resilience modulus and disperse characteristics of Rayleigh wave in subgrade with giant grain of soil,additional mass method used to get density and vertical wave in subgrade with giant grain of soil.Then the paper puts the results as the initial value to inverse Rayleigh shear wave speed,on a weighted average of the subgrade layer thickness to gain the calculated mode of dynamic resilience modulus in giant grain of soil subgrade.Using MASW,which developed by Chongqing Traffic Research Institute independently,to deal with data from wave detection and inverse Rayleigh shear wave speed.Thus calculates dynamic modulus and verifies it by the results from FWD (Falling Weight Deflectometer).Finally,the results from Rayleigh wave method used in practical engineering projects show that the additional mass method used to calculate giant grain subgrade dry density can get a high precision compared with the water replacement method,so it can be used as the initial value to inverse shear wave speed;although the dynamic resilience modulus got by Rayleigh wave method has certain error compared with test results from FWD,it can meet certain error range,so it can be acceptable in engineering. Therefore,the dynamic resilience modulus detected by Rayleigh wave method used to evaluate construction quality of the subgrade with giant grain is feasible. |
