基于支持向量机的注浆锚杆锚固参数反分析

Back Analysis of Pullout Strength Parameters for Grouted Anchor Bolt Based on Support Vector Machine

注浆锚杆极限抗拔力一般通过现场试验进行测定,但在锚固工程数值模拟分析过程中,所需的锚固参数(如注浆体的黏结强度和摩擦角)很难直接确定。提出了一种基于支持向量机的注浆锚杆锚固参数反分析方法,即利用锚杆极限抗拔力反分析锚固参数。选取锚杆极限抗拔力作为实测目标,结合均匀试验和支持向量机建立锚固参数与实测目标之间的映射关系,通过蒙特卡洛法枚举大量锚固参数样本,利用上述已建立的映射关系计算枚举的锚固参数样本,得到对应目标的计算值。在此基础上,根据目标实测值筛分得到符合条件的目标计算值对应的锚固参数,并通过关于注浆锚杆的模型案例说明了该方法的可行性。

As a kind of effective and economic reinforcement means,the grouted anchor bolt has been widely used in slope and tunnel engineering. The ultimate pullout force of anchor bolt is usually obtained by field test. However,in the process of numerical simulation analysis for anchoring engineering,the pullout strength parameters,such as the cohesive strength and friction angle of grouting body is difficult to determine directly. Therefore,a back analysis method of pullout strength parameters for grouted anchor bolt based on support vector machine( SVM) was proposed in this paper. The ultimate pullout force of anchor bolt was selected as the measured target in order to obtain the pullout strength parameters. Combined with uniform testing and SVM,the response relationship between the pullout strength parameters and the measured target was established. The Monte Carlo method was used for enumerating the samples of pullout strength parameters that were calculated by the established response relationship in order to obtain the calculated values of target. According to the measured target values,the calculated values were screened in order to get the pullout strength parameters that correspond to the qualified calculated values. Finally,it showed that the method was feasible through a case analysis about grouted anchor bolt.