基于贝雷法与泰波法的孔隙型水泥稳定碎石设计

以孔隙率为设计指标,综合了贝雷法和泰波法的混合料设计方法,可以计算出孔隙型水泥稳定碎石中粗集料、细集料用量,进而确定混合料的级配,可用于孔隙型水泥稳定碎石材料设计。采用这一方法完成了孔隙型水泥稳定碎石的设计,通过试验,以有效孔隙率、无侧限抗压强度和劈裂强度为指标,分析了基于贝雷法与泰波法设计的混合料的性能。结果表明:有效孔隙率与理论孔隙率成正相关,以理论孔隙率为设计指标,可以实现较高的有效孔隙率;增加填充料的用量,可以显著提高混合料的无侧限抗压强度和劈裂强度,但随着填充料的增加,其对混合料强度的影响越来越小。

道路基层材料级配设计试验研究

级配的好坏对道路基层材料性能的影响很大。为了研究0~19mm粒径范围内集料的最优级配,采用逐级填充法和泰波n法分别对粗集料和细集料进行级配设计,得到粗集料和细集料的最优级配。再将优化后的粗集料和细集料的级配按比例混合,掺加5%的水泥后进行击实试验和7d无侧限抗压强度试验,得到0~19mm粒径范围集料的最优级配。结果表明,当19、16、13.2、9.5、4.75mm集料的筛分通过率依次为100%、89.9%、100%、77.5%、50%时,0~19mm粒径范围内集料最密实。当集料粒径尺寸越小,粒径越小集料在4.75~19mm集料的占比就越大。当n取0.5时,35%细集料和45%细集料的级配在规范的限值之内:当19、16、13.2、9.5、4.75、2.36、0.6、0.3、0.15、0.075mm集料的筛孔通过率分别为100%、91.9%、84.5%、70.3%、40.0%、28.2%、19.9%、14.2%、10%、7%、5%时,水稳碎石基层材料的抗压强度值最大。

K2_SPH Method and its Application for 2-D Water Wave Simulation

Smoothed Particle Hydrodynamics (SPH) is a Lagrangian meshless particle method. However, its low accuracy of kernel approximation when particles are distributed disorderly or located near the boundary is an obstacle standing in the way of its wide application. Adopting the Taylor series expansion method and solving the integral equation matrix, the second order kernel approximation method can be obtained, namely K2_SPH, which is discussed in this paper. This method is similar to the Finite Particle Method. With the improvement of kernel approximation, some numerical techniques should be adopted for different types of boundaries, such as a free surface boundary and solid boundary, which are two key numerical techniques of K2_SPH for water wave simulation. This paper gives some numerical results of two dimensional water wave simulations involving standing wave and sloshing tank problems by using K2_SPH. From the comparison of simulation results, the K2_SPH method is more reliable than standard SPH.