岩土力学
巖土力學
암토역학
ROCK AND SOIL MECHANICS
2014年
1期
7-24
,共18页
朱启银%尹振宇%朱俊高%王建华%夏小和
硃啟銀%尹振宇%硃俊高%王建華%夏小和
주계은%윤진우%주준고%왕건화%하소화
软黏土%先期固结压力%抗剪强度%速率效应%应力剪胀%等应变率%香港海积相沉积物
軟黏土%先期固結壓力%抗剪彊度%速率效應%應力剪脹%等應變率%香港海積相沉積物
연점토%선기고결압력%항전강도%속솔효응%응력전창%등응변솔%향항해적상침적물
soft clay%preconsolidation pressure%shear strength%rate-dependency%stress-dilatancy%constant ratio of stain(CRS)%Hong Kong marine deposits (HKMD)
大量的室内和现场试验都表明,软黏土的强度与变形速率相关。为了更深入地认识软黏土的加载速率效应特性,首先分析了一维应力条件下先期固结压力和三轴应力条件下不排水抗剪强度的加载速率效应及应力-应变关系的归一化,探讨了一维和三轴条件下的5个速率方程(2个指数形式和3个对数形式)在拟合黏土先期固结压力和不排水强度加载速率效应上的适用性;使用5个速率方程估计了一维和三轴条件下的加载速率参数,以及拟合了加载速率参数与液塑限的关系,并且分析了复杂应力(十字板剪切和旁压条件)下的非理想土单元体的黏土加载速率效应特性等;讨论了黏土加载速率效应特性在一维和三维、压缩与伸长、不同超固结比(OCR)条件下的统一性;最后,从香港黏土压缩与伸长和不同OCR条件下的剪缩、剪胀特性方面更深入地探讨了软黏土加载速率效应特性,并讨论了典型的剪缩、剪胀方程在黏土的力学特性模拟中的有效性。结果表明,为更好地描述黏土的应力剪胀特性,现有典型的剪胀关系需要更一步改进。
大量的室內和現場試驗都錶明,軟黏土的彊度與變形速率相關。為瞭更深入地認識軟黏土的加載速率效應特性,首先分析瞭一維應力條件下先期固結壓力和三軸應力條件下不排水抗剪彊度的加載速率效應及應力-應變關繫的歸一化,探討瞭一維和三軸條件下的5箇速率方程(2箇指數形式和3箇對數形式)在擬閤黏土先期固結壓力和不排水彊度加載速率效應上的適用性;使用5箇速率方程估計瞭一維和三軸條件下的加載速率參數,以及擬閤瞭加載速率參數與液塑限的關繫,併且分析瞭複雜應力(十字闆剪切和徬壓條件)下的非理想土單元體的黏土加載速率效應特性等;討論瞭黏土加載速率效應特性在一維和三維、壓縮與伸長、不同超固結比(OCR)條件下的統一性;最後,從香港黏土壓縮與伸長和不同OCR條件下的剪縮、剪脹特性方麵更深入地探討瞭軟黏土加載速率效應特性,併討論瞭典型的剪縮、剪脹方程在黏土的力學特性模擬中的有效性。結果錶明,為更好地描述黏土的應力剪脹特性,現有典型的剪脹關繫需要更一步改進。
대량적실내화현장시험도표명,연점토적강도여변형속솔상관。위료경심입지인식연점토적가재속솔효응특성,수선분석료일유응력조건하선기고결압력화삼축응력조건하불배수항전강도적가재속솔효응급응력-응변관계적귀일화,탐토료일유화삼축조건하적5개속솔방정(2개지수형식화3개대수형식)재의합점토선기고결압력화불배수강도가재속솔효응상적괄용성;사용5개속솔방정고계료일유화삼축조건하적가재속솔삼수,이급의합료가재속솔삼수여액소한적관계,병차분석료복잡응력(십자판전절화방압조건)하적비이상토단원체적점토가재속솔효응특성등;토론료점토가재속솔효응특성재일유화삼유、압축여신장、불동초고결비(OCR)조건하적통일성;최후,종향항점토압축여신장화불동OCR조건하적전축、전창특성방면경심입지탐토료연점토가재속솔효응특성,병토론료전형적전축、전창방정재점토적역학특성모의중적유효성。결과표명,위경호지묘술점토적응력전창특성,현유전형적전창관계수요경일보개진。
Extensive laboratory tests and field observations show that soft clay exhibits significant rate-dependent behavior. Based on published data from the view of the rate dependencies of preconsolidation pressure and undrained shear strength. The rate-dependencies of soft clays under both 1D and 3D conditions are first studied. The applicability of five rate-dependency equations (two equations in exponential form and three equations in logarithmic form) in correlating the preconsolidation pressure and the undrained shear strength with strain-rate is then discussed. Rate parameters under both 1D and 3D conditions for various clays are estimated by using five rate-dependency equations and correlated with Atterberg limits. Furthermore, the rate-dependencies of soft clays under complex stress conditions including shear vane tests and pressuremeter tests are also analyzed. Then, the uniqueness of rate-dependency between 1D and 3D, between triaxial compression and extension, between different OCR (over consolidation ration) conditions is discussed. Finally, the influence of applied strain-rate on the stress-dilatancy of Hong Kong marine clay for triaxial compression and tension tests under different OCR conditions is investigated with some typical stress-dilatancy equations. The results show that the existing typical stress-dilatancy relationships need further enhancement (e.g., amount, anisotropy) for better describing the stress-dilatancy of soft clays.