A Study of the Correlations among In-Situ Penetration Test Data of Sandy Soil

• Main Authors: Chia-Yi Ho, 何佳憶
• Other Authors: Chih-Sheng Ku
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/45578267043970098117

碩士 === 義守大學 === 土木與生態工程學系碩士班 === 96 === The Penetration Test is an in-situ method employed to investigate soil layers and soil properties. The most widely used one in Taiwan is Standard Penetration Test(SPT) which provides N-values and permits acquisition of split-tube samples. The Cone Penetration Test(CPT) is one which can provide accurate and nearly continuous soil profiles. Both methods are vertical-penetration type. An improved third method, the Flat Dilatometer Test (DMT), exerts a lateral pressure on the soil after reaching pre-selected penetration depths, and measures the lateral stress as well as deformation. All three methods are useful in yielding soil-related parameters needed in design and construction. In this study, data from six sandy-soil sites where all three methods were utilized to acquire in-situ soil properties are used to carry out correlation analyses of the following parameters: CPT-qc, CPT-fs, and SPT-N. In terms of establishing soil classification, CPT and DMT agree well with the basic SPT, except for thin layers. For continuous homogeneous soil layers, the SPT-N values separately estimated form the CPT and DMT data are nearly identical. CPT-qc is similar to the end bearing of a small pile, CPT-fs increase with the increment of the normal stress of the sleeve surface. DMT-P0 and P1 are regard to the different level passive soil pressure. Those values are function of the internal friction angle (?) in the sandy soil. Data from six sandy sites show that CPT cone resistance (qc) is about the 4.2-5.6 times of the DMT expansion pressure (p1). The ratio of the CPT local friction (fs) with DMT contact pressure (p0) is about 5.6-6.6.