細料含量對粉土細砂不排水強度的影響

Abstract

在過去四十年間，室內試驗關於控制乾淨砂不排水應力應變行為與抗液化強度的影響因子，已經有相當好的結果。在自然界中，許多的天然砂土都具有細粒料；根據現地液化後的觀察結果，含細粒料的砂土其液化行為不同於乾淨砂。因此，學者們開始研究粉土砂的應力－應變行為、穩定狀態強度與抗液化強度，以了解細粒料含量對於粉土砂的影響。然而，關於細粒料含量對於粉土砂力學行為的影響，至今仍然不甚清楚。研究使用的麥寮砂（MLS）為台灣西部海岸的典型砂土，具有相當高含量的粉土（silt）。根據試驗結果顯示，麥寮砂具有高壓縮性而膨脹性不高的特性。 研究主要目的是了解細粒料含量對於麥寮粉土細砂力學行為的影響。藉著進行麥寮砂不同細粒料含量的穩定狀態強度與抗液化強度，來分析細粒料的影響。本論文敘述研究之背景、目的、進行步驟、試驗程序與試驗結果資料，對於粉砂中穩定狀態強度與抗液化強度結果進行分析、討論並提供建議。

During the past 40 years, the laboratory study on undrained stress-strain behaviour and seismic loads of clean sands has been studied well and a sound understanding of its mechanisms and the parameters that control it have been developed. In field, there are many natural sandy soils have a mount of fines and have different behavior with clean sands. Therefore several researchers have begun to study the effect of fines on stress-strain behavior, steady state strength, and cyclic strength. However, there is no clear consensus as to what effect an increase in nonplastic silt content has upon the liquefaction resistance of sand. The main objective of this research project is to evaluate the effect of fines on steady state strength and cyclic strength for Mai Liao silty sand（MLS）. MLS is a typical sand on the West Coast of Taiwan, the sand is compressible and has a less tendency to dilate. This thesis describes the background of the research, it’s objectives, research approach, procedures of the static triaxial test and the cyclic triaxial test and test results. Test results are analyzed and declared the influence of silt on Mai Liao silty sand.