以實驗方法探討非飽和含皂土細粒料砂土之液化行為研究

Abstract

地球上每年都會發生許多地震，臺灣更是高度好發地震地區，這些地震往往對建築物和人民生命造成嚴重的破壞。地震引發的問題之一就是液化，液化現象對我們的結構物會造成難以控制的影響。然而，大多數對抗液化的研究都集中在飽和沙土方面，未飽和沙土或含有不同細粒料的沙土卻未受到足夠的關注。為了更好地了解這些土壤的液化特性，我將對不同的飽和度和皂土含量下的沙土進行一系列動態三軸試驗。不同飽和度、黏土粒料含量之試體在加載不同的循環應力之後可以計算得可以計算得各試體之CSR以及LRR，並進行流量幫浦試驗以獲取土壤水特性曲線（SWCC）。在流量幫浦試驗期間，每個試體提取的水量會被控制以達到預期的飽和度。在進行循環動態加載時，將監測試體之孔隙氣壓、孔隙水壓和基質吸力的變化。最後，將討論皂土含量和基質吸力之間的關係，並根據這一系列實驗研究的結果評估含皂土細粒料之未飽和土壤的抗液化能力。 動態三軸試驗是用於評估土壤動態強度的一種常用實驗方法，通過對土壤進行壓密和施加循環剪切應力，可以了解其變形和破壞特性。CSR和LRR是評估土壤液化特性的重要參數，能夠幫助我們預測在地震等自然災害中土壤的反應。另外，流量幫浦試驗是一種測量土壤水力特性曲線（SWCC）的有效方法，可以獲得土壤基質吸力曲線、孔隙比和飽和度

Taiwan experiences a high frequency of earthquakes every year, which often result in significant damages to buildings and human life. One of the major issues caused by earthquakes is liquefaction, a problem that requires our attention. Liquefaction can have an uncontrollable impact on our country. Most research related to liquefaction focused on saturated sands, unsaturated sands or sands containing fines have received less attention. To better understand the liquefaction properties of such soils, a series of cyclic triaxial tests were conducted under varying degrees of saturation and fines content in this study. Flow pump tests were performed to obtain the soil water characteristic curve (SWCC). Water extracted from each specimen during the pump test would be controlled to achieve the intended degree of saturation. During the application of cyclic loading, changes in pore air pressure, pore water pressure, and matric suction were monitored. The cyclic shear resistance (CSR) and liquefaction resistance ratio (LRR) were determined and compared with those for saturated material. It’s observed that saturated sand with plastic fines can liquefy, but as the degree of saturation decreases, the liquefaction resistance significantly increases. Also, the addition of bentonite in silica sand provides a more noticeable increase in liquefaction resistance compared to the addition of silt or kaolinite.