Behavior of Shear Wave Velocity of Compacted Soils

• Main Authors: Liu, Ru-Zheng, 柳儒錚
• Other Authors: Lin, Chih-Ping
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/90842409128452334209

碩士 === 國立交通大學 === 土木工程學系 === 98 === Quality control of compacted soils is important in earth dam, levee, retaining wall backfill...etc. To develope a new measurement technique incorporating both electromagnetic wave based on Time domain reflecmetry(TDR) and Shear wave velocity, it is necessary to first figure out the behavior of Shear wave velocity in compacted soils. In order to measure shear wave velocity of compacted soils, bender element(BE) method is performed in laboratory, and the purpose of experiment were divided into two parts: investigating the influence soil fabric on shear wave velocity of compacted soil, and to figure out the relationship between soil phase parameters and shear wave velocity. Experimental results show that soil fabric of fine soils does affect the behavior of shear wave velocity in compacted soils under the same dry density and water content, and the shear wave velocity of the compacted soil has a linear relationship with the degree of saturation if it is between 40%~90%, the semi-theoretical model( Fratta et al. 2005) was successfully applied to analyze the data. However, it requires varying the water content to be able to measure water content and dry density in the field. Alternatively, an empirical formula ( V_s=a_s+b_s×S^m) was found to well describe the shear wave velocity in terms of degree of saturation of freshly-compacted soil. Through this function, a method combined with surface wave testing and TDR technology was proposed. Preliminary laboratory results show that the proposed method can achieve 3% accuracy in dry density and 1% accuracy in water content.