基于LADE-DUNCAN模型的生物酶改良膨胀土弹塑性本构关系研究  

Study on elasto-plastic constitutive relation of bioenzyme-treated expansive soil based on LADE-DUNCAN model

作　　者：文畅平 WEN Changping(School of Civil Engineering,Central South University of Forestry and Technology,Changsha 410018,China;Hunan Engineering Laboratory for Manufacturing and Application Technology of Modern Timber Structural Engineering Materials,Central South University of Forestry and Technology,Changsha 410018,China)

机构地区：[1]中南林业科技大学土木工程学院,湖南长沙410018 [2]中南林业科技大学现代木结构工程材制造及应用技术湖南省工程实验室,湖南长沙410018

出　　处：《中南大学学报（自然科学版）》2021年第11期4190-4200,共11页Journal of Central South University:Science and Technology

基　　金：国家国际科技合作专项(2014DFA53120);现代木结构工程材制造及应用技术湖南省工程实验室开放基金资助项目(HELFMTS1707);湖南省重点学科建设项目(2013ZDXK006)。

摘　　要：基于LADE-DUNCAN模型,研究生物酶改良膨胀土的弹塑性应力−应变关系。首先,开展一系列三轴固结排水剪切试验,得到偏应力q与轴向应变ε_(1)、体应变ε_(v)、侧向应变ε_(3)之间的试验曲线;然后,采用黏结应力σ_(0)修正LADE-DUNCAN屈服准则;最后,根据三轴试验结果拟合LADE-DUNCAN模型中的各参数与生物酶掺量之间的关系表达式,建立基于生物酶掺量的LADE-DUNCAN弹塑性本构模型。研究结果表明:在不同生物酶掺量下,偏应力q与轴向应变ε_(1)均表现为硬化型的应力−应变关系,偏应力q与体应变ε_(v)均表现为剪缩型的应力−应变关系,q与ε_(1),ε_(v)与ε_(1)和q与ε_(3)等试验曲线均近似为双曲线;黏结应力σ_(0)修正的LADE-DUNCAN屈服准则可以很好地描述生物酶改良膨胀土的应变硬化、应变剪缩;应力−应变本构方程可以较好地预测出不同生物酶掺量、不同围压σ_(3)下的生物酶改良膨胀土的应力−应变关系。The elasto-plastic stress-strain behavior of bioenzyme-treated expansive soil was studied based on LADE-DUNCAN model.Firstly,according to a series of the triaxial consolidated drained shear tests of bioenzyme-treated expansive soil at different percentages of bioenzyme,the test curves including deviator stress q and axial strainε_(1),bulk strainε_(v),lateral strainε_(3) were obtained,respectively.Secondly,bond stressσ_(0) was used to modify LADE-DUNCAN yield criterion.Finally,the expressions between the parameters of LADE-DUNCAN model and percentage of bioenzyme were fitted based on the triaxial test results.A LADE-DUNCAN elasto-plastic constitutive model based on the percentage of bioenzyme was proposed.The results show that the stress-strain relationships between deviator stress q and axial strainε_(1)is strain hardening,deviator stress q and bulk strainε_(v)is shrinkage,and the test curves between q andε_(1),ε_(v)andε_(1)and q andε_(3)are hyperbola at different ratios of bioenzyme-based soil stabilizer.The behaviors of strain hardening and strain shrinkage of bioenzyme-treated expansive soil can be better described according to modified LADE-DUNCAN yield criterion by bond stressσ_(0).The stress-strain relationship of bioenzyme-treated expansive soil at different percentages of bioenzyme and confining pressuresσ3 can be well predicted based on the proposed stress-strain constitutive equation.

关 键 词：生物酶改良膨胀土 LADE-DUNCAN模型 弹塑性本构关系 

分 类 号：U416.1[交通运输工程—道路与铁道工程]