摘要
为揭示引黄入洛深埋隧洞新近系饱和砂的工程特性,进行了动强度试验,研究其在不同初始固结围压σ3和密实度下的动强度特性。试验结果表明:试验中主要表现为中部鼓胀式压缩和中部收缩式拉伸两种破坏形式;动剪应力τf随σ3的增大而增大,当σ3为200 kPa时,动剪强度值有较大提高;相同σ3下,动剪应力随密实度的增大而增大,动强度曲线即动剪应力与振动次数的关系曲线可拟合为直线,并呈负相关关系,动剪应力比随着密实度的增大而增大;高密实度时,各振动次数下的τf—σ3曲线重合,说明高密实度下较小的扰动就会导致砂样破坏;动摩擦角随密实度的增大而增大,随振动次数的增加而减小,振动次数对动摩擦角的影响随密实度的增大而减小。根据试验结果,施工中应采取有效措施降低未胶结砂的含水率,提高其密实度,尽量减少施工扰动。
In order to reveal the engineering characteristics of Neogene saturated sands in deep tunnel of diverting the Yellow River into Luoyang and study the dynamic strength characteristics under various initial consolidation pressures σ3 and densities, the dynamic strength tests were done and show that： it has two failure modes in the test that are middle bulge type compression and middle contraction type tensile. The dynamic shear stress increases with the increasing of σ3, and its increasing extent is larger when σ3 is 200 kPa. The dynamic shear stress increases with the increasing of relative density, and the dynamic strength curve-the correlation between dynamic shear stress rf and the vibration frequency can be fit into straight line with the negative correlation under the same consolidation pressure σ3 and the dynamic shear stress ratio increases with the increasing of relative density. The curve of rf and σ3 coincide each vibration in high density, so the sample of sand may damage resulting from less disturbance in the condition of higher relative density. The value of dynamic friction angle increases with the increasing of relative density, and decreases with the increasing of the number of vibration, and the influence of the number of vibration on dynamic friction angle reduce with the increasing of relative density. Based on the study, the effectively constructing measure must be adopted to decrease the moisture content and enhance the relative density of Neogene sand and reduce the constructing disturbance as much as possible.
出处
《人民黄河》
CAS
北大核心
2016年第4期129-132,共4页
Yellow River
基金
2015年度河南省基础与前沿技术研究项目(152300410216)
关键词
新近系饱和砂
初始围压
固结围压
密实度
动强度特性
Neogene saturated sand
initial pressure
consolidation pressure
relative density
dynamic strength characteristics
