晋江围海工程黏性原状土冲刷率试验研究

Scour rate experimental research on cohesive undisturbed soil from the reclamation project in Jinjiang

通过物理模型试验,对福建晋江围海工程的6组粉沙、8组细沙、7组中粗沙原状土样进行冲刷率试验。根据实测的冲刷率和床面切应力来分析原状泥沙的冲刷率表达式。考虑中值粒径对冲刷率表达式的影响,分别得出了粉沙、细沙、中粗沙的冲刷率表达式中的能量指数和冲刷系数。结果表明:粉沙、细沙、中粗沙的冲刷率分别与相对剩余切应力的0.5次方、1次方、1.25次方成正比,且随着粒径的增大,冲刷系数逐渐减小,中粗沙的冲刷系数仅为粉沙的十分之一。此外,粒径较小的粉沙和细沙的冲刷系数有随土样黏性颗粒含量的增加而成非线性减小的趋势,黏性颗粒含量较小的中粗沙的冲刷系数则随着黏性颗粒含量的增加无明显关系。

Based on physical model test, six groups samples of silt, eight groups samples of fine sand and seven groups samples of medium coarse sand from the reclamation project in Jinjiang, Fujian were tested for the scour rate. The scour rate formula of cohesive undisturbed soil was analyzed according to the measured scour rate and bed shear stress. The impact of median diameter on the value of the scour rate formula was considered, the energy index and scour coefficient of scour rate formula for the silt, fine sand, medium coarse sand were obtained separately. The text result shows that for those silt, the scour rate and the relative residual shear stress is proportional to the 0.5, there is＇a linear relationship between scour rate and the relatively residual shear stress for fine sand, besides, the scour rate and relatively surplus shear stress of medium coarse sand is proportional to the 1.25. And the scour coeffi- cient has a tendency to decrease with the increasing of median diameter, the scour coefficient of medium coarse sand only one-tenth of the silt. In addition, the scour coefficient of silt and fine sand have a non-linear tendency to decrease with the increasing of clay content, however, the scour coefficient of the medium coarse sand which have smaller particle clay content has no significant relationship with the increasing of clay particles.