疏浚饱和密实粉土剪胀特性及其对耙齿切削阻力的影响

Shear dilation characteristic of dredging saturated dense silt soil and effect on cutting resistance of rake tooth

针对黄骅港区饱和密实粉土,通过三轴剪切试验以及原型耙齿切削试验,研究饱和密实粉土剪胀特性及其对耙齿切削阻力的影响。三轴试验结果表明,黄骅地区饱和密实粉土在剪切过程中表现为应变软化性状,偏应力峰值与围压之间基本呈线性关系。在剪切过程中,土体先剪缩后剪胀,随着围压的增大,剪缩性状体现得越来越明显,应力应变性状可划分为4个不同阶段。原型耙齿切削试验结果表明,饱和土较非饱和土切削阻力增长得更快;饱和土切削阻力最大值为非饱和土切削阻力最大值的2.7~3.3倍;对于饱和土,切削阻力达到稳定值后,其波动幅度较非饱和土要大。上述试验结果均表明,土的剪胀性对于耙齿切削阻力的影响十分显著,须采取相应的措施来降低土的剪胀性对于耙齿切削阻力的影响。

Through a series of triaxial shear tests and soil cutting tests with prototype rake tooth in Huanghua port area, we probe into the shear dilation characteristic of the saturated dense silt and its influence on the cutting resistance of the rake tooth. The triaxial test results show that the saturated dense silt in Huanghua area exhibits significant strain softening during the shear process. The relationship between the peak stress and the confining pressure is nearly linear.In shearing process, the soil shows shear contraction and then dilatancy.With the increase of confining pressure, the properties of shear contraction are more and more obvious.The stress-strain curve should be divided into 4 different stages.The soil cutting tests with prototype rake tooth show that the cutting resistance of the saturated soil grows faster than that of the unsaturated soil.The maximum value of the cutting resistance of saturated soil is 2.7- 3.3 times as that of unsaturated soil.For the saturated soil, the fluctuation range is larger than that of the unsaturated soil after the cutting resistance is stable.The test results show that the soil dilatancy effect on the cutting resistance of the rake tooth is very significant and appropriate measures for reducing the influence of dilatancy on the cutting resistance should be taken.