摘要
为提高上海地区黏土的工程特性,采用纤维素纤维改良黏土的方法,通过击实试验、直接剪切试验和无侧限抗压强度试验,来探究不同加筋条件下纤维素纤维对上海黏土的最优含水率、最大干密度、抗剪强度以及抗压强度等力学特性的影响。试验结果表明:纤维素纤维可增大黏土的最大干密度,减小黏土的最优含水量,且随着纤维加筋率和含水率的增大,影响逐渐降低。与素土相比,纤维素纤维加筋土的抗剪强度明显增强,最优加筋率为0.6%。当纤维素纤维加筋率低于0.6%时,不同垂直荷载下的抗剪强度均随着纤维含量的增加而提高,当纤维素纤维加筋率高于0.6%时,加筋土的抗剪强度则逐渐下降。直接剪切试验中,垂直荷载为50 k Pa和100 k Pa时,多数应力应变曲线呈现应变软化型;150 k Pa和200 k Pa时,多数应力应变曲线呈现应变硬化型。当纤维素纤维加筋率为0.6%时,纤维素纤维可明显提高黏土的抗压强度,纤维加筋率过高时,纤维素纤维对黏土无侧限抗压强度的影响减弱。纤维素纤维可增强黏土整体性、受外力作用时的稳定性,纤维加筋率过高时,抗压强度和抵抗变形的能力减小。由此说明,纤维素纤维可在一定程度上增强黏土的密实度、抗剪强度和抗压强度,优化黏土破坏形态。同时,过量的纤维素纤维将引起反作用。
To improve the mechanical property of clay in Shanghai, adopting the method for improving clay with cellulose fiber, the effects of cellulose fiber on optimum moisture content, maximum dry density, shear strength and compressive strength of clay under different reinforcing conditions are studied by compaction test, direct shear test and unconfined compression strength test. The experimental result indicates that （ 1 ） cellulose fiber can increase the maximum dry density and reduce the optimal water eontent of clay, and the influence decreases gradually with the increase of reinforcement rate and moisture content of the fiber; （2） compared with plain soil, the shear strength of cellulose fiber reinforced clay is obviously enhanced, the optimal reinforeement rate is 0. 6% ; （3） when the reinforcement ratio of eellulose fiber is less than 0. 6% , the shear strength under different vertical loads increases with the increase of fiber content, while when the reinforcement ratio of cellulose fiber is higher than 0. 6% , the shear strength of reinforced clay decreases gradually; （4） in the direct shear test, most of the stress-strain curves show strain-softening behavior under 50 kPa and 100 kPa vertical loads, and most of the stress-strain curves show strain hardening under 150 kPa and 200 kPa vertical loads; （5） when the reinforcement ratio of cellulose fiber is 0. 6%, the compressive strength of clay can be obviously increased by cellulose fiber, but when the fiber reinforcement ratio is too high, the influence of cellulose fiber on the unconfined compressive strength of clay is weakened; （6） cellulose fiber can enhance the integrity and the stability of the clay under external force, the compressive strength and resistance to defomaation will decrease shear strength when the fiber reinforcement rate is too high. Therefore, cellulose fiber can enhance the density, the and the compressive strength of clay, and optimize the clay damage morphology to a certain extent. At the same time, excessive
出处
《公路交通科技》
CAS
CSCD
北大核心
2018年第1期22-27,35,共7页
Journal of Highway and Transportation Research and Development
关键词
道路工程
纤维素纤维
直接剪切试验
抗剪强度
加筋土
无侧限抗压强度
road engineering
cellulose fiber
direct shear test
shear strength
reinforced clay
unconfined compressive strength
