砂土的狀態(tài)主要取決于孔隙比(密實(shí)度)和圍壓大小,它們極大地影響了砂土的力學(xué)特性(壓縮性、剪脹性和液化性)。為研究低圍壓至高圍壓范圍內(nèi)砂土相對密度和圍壓對土體強(qiáng)度和變形特性的影響,對2種不同相對密實(shí)度砂土試樣在低至高圍壓下(5～3 MPa)進(jìn)行常規(guī)三軸固結(jié)排水剪切試驗(yàn)、常規(guī)三軸固結(jié)不排水試驗(yàn)和動三軸非排水試驗(yàn),對砂土的靜、動變形特性及靜、動強(qiáng)度特性進(jìn)行研究。試驗(yàn)結(jié)果表明:在單調(diào)加載條件下,在低圍壓范圍(5～20 kPa),體積應(yīng)變由剪縮向剪脹轉(zhuǎn)變,且剪脹角具有明顯的應(yīng)力依存性,隨著圍壓的減小而增大;在高圍壓范圍(1～3 MPa),試樣體積逐漸趨于剪縮;在循環(huán)加載條件下,砂土試樣抵抗液化能力隨著圍壓的減小而增強(qiáng),軸向應(yīng)變伴隨著圍壓的增大從壓縮狀態(tài)向膨脹狀態(tài)轉(zhuǎn)變。同時,試驗(yàn)結(jié)果表明,應(yīng)用文中的試驗(yàn)方法,橡皮膜的約束效應(yīng)對低圍壓的試驗(yàn)結(jié)果影響較小。

【文章頁數(shù)】：14 頁

【文章目錄】：
1 Introduction
2 Test program
    2.1 Apparatus for triaxial test
    2.2 Preparation for test specimens
    2.3 Testing procedure
3 Void ratio dependency
    3.1 Results from monotonic loading
    3.2 Results from cyclic loading
4 Confining stress dependency
    4.1 A state variable in monotonic drained/undrained tests
    4.2 Dilation behaviors in monotonic drained/undrained tests
    4.3 Liquefaction behavior in cyclic undrained triaxial test
5 Reproducibility of test results and membrane thickness effect
    5.1 Reproducibility of experimental results
    5.2 Influence of membrane thickness
6 Conclusions



本文編號：3992845