水泥土蠕变声发射特性及损伤试验研究
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摘要
为了探究水泥土在长期荷载作用下内部微观结构损伤变形的变化规律,采用声发射这一无损监测手段对不同龄期下的水泥土进行了单轴蠕变声发射监测试验。研究结果表明:水泥土的强度随龄期呈幂函数增长;水泥土具有较强的软土流变特征,龄期越长,初始蠕变量和稳态蠕变速率越低;水泥土的声发射活跃程度随着龄期的增长而增加,这主要与水泥土内部土颗粒与水泥之间相互作用产生的微观结构相关,龄期短时主要以摩擦和滑移信号为主,龄期长时,除了摩擦和滑移信号,还伴随着晶粒的位错、断裂信号;声发射参数累计值与蠕变曲线特征一致;基于weibull分布函数,得到了基于声发射参数的水泥土蠕变损伤本构模型,能很好模拟各龄期下水泥土的损伤变形特征;龄期越长,均质性系数m越大。
For the purpose of exploring the change rule for damage deformation of internal microstructure of cement soil under long-term load,the acoustic emission(nondestructive monitoring method) is adopted for the uniaxial creep acoustic emission monitoring test of cement soul under different ages. The research result indicates that:the strength of cement soil increases in the power function with the growth of age. The cement soil possesses stronger rheological characteristics of soft soil. The longer the age is,the lower the initial creep variable and the steady creep rate are. The activity degree of acoustic emission of cement soil increases with the growth of age,which is mainly related to the microstructure generated due to the interaction between the internal soil particles of cement soil and the cement. The acoustic emission focuses on the friction and slip signal when the age is short,while it is accompanied with the dislocation and fracture signal of grain in addition to the friction and slip signal when the age is long. The accumulated value of acoustic emission parameters is consistent with the creep curve characteristics. Based on the distribution function of weibull,the constitutive model for creep damage of cement soil based on the acoustic emission parameter is worked out and could simulate the damage deformation characteristics of cement soil at different ages very well. The longer the age is,the larger the uniformity coefficient(m) is.
For the purpose of exploring the change rule for damage deformation of internal microstructure of cement soil under long-term load,the acoustic emission(nondestructive monitoring method) is adopted for the uniaxial creep acoustic emission monitoring test of cement soul under different ages. The research result indicates that:the strength of cement soil increases in the power function with the growth of age. The cement soil possesses stronger rheological characteristics of soft soil. The longer the age is,the lower the initial creep variable and the steady creep rate are. The activity degree of acoustic emission of cement soil increases with the growth of age,which is mainly related to the microstructure generated due to the interaction between the internal soil particles of cement soil and the cement. The acoustic emission focuses on the friction and slip signal when the age is short,while it is accompanied with the dislocation and fracture signal of grain in addition to the friction and slip signal when the age is long. The accumulated value of acoustic emission parameters is consistent with the creep curve characteristics. Based on the distribution function of weibull,the constitutive model for creep damage of cement soil based on the acoustic emission parameter is worked out and could simulate the damage deformation characteristics of cement soil at different ages very well. The longer the age is,the larger the uniformity coefficient(m) is.
引文
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[ 2 ] 庞文台.掺合粉煤灰的复合水泥土力学性能及耐久性试验研究[D].呼和浩特:内蒙古农业大学,2013.
[ 3 ] 陈达,庄宁,廖迎娣,等.水泥土力学特性随龄期发展规律试验研究[J].水利水运工程学报,2012,(1):26-29.
[ 4 ] 赵程,申向东,贾尚华,等.密实度对压实水泥土强度的影响[J].岩土工程学报,2013,35(增刊1):360-365.
[ 5 ] 董晓强,苏楠楠,黄新恩,等.污水浸泡对水泥土强度和电阻率特性影响的试验研究[J].岩土力学,2014,35(7):1856-1862,1870.
[ 6 ] 韩鹏举,白晓红,赵永强,等.Mg(2+)和SO相互影响对水泥土强度影响的试验研究[J].岩土工程学报,2009,31(1):72-76.
[ 7 ] 贾志清.含盐量对水泥土强度影响的试验研究[J].交通标准化,2008,(13):87-89.
[ 8 ] 陈四利,史建军,于涛,等.冻融循环对水泥土力学特性的影响[J].应用基础与工程科学学报,2014,22(2):343-349.
[ 9 ] 郭少龙,鹿群,王闵闵,等.水泥土流变特性的试验研究[J].地下空间与工程学报,2016,12(增刊2):445-451.
[10] 樊怀仁.水泥土桩复合地基的流变分析[J].长安大学学报:自然科学版,2002,22(5):17-19.
[11] 秦艳华,张帆,王军.土的流变性及其在水泥土搅拌桩复合地基中的应用[J].铁道建筑,2005,(2):84-87.
[12] 王祖荫.声发射技术基础[M].山东:山东科技大学出版社,1990.
[13] 唐春安,徐小荷.岩石破裂过程中的灾变问题[C]//第四届全国岩石破碎学术讨论会论文集.成都,1989.