DE-GWO算法优化SVM反演软土力学参数
DE-GWO algorithm to optimize SVM inversion mechanical parameters of soft soil
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摘要: 岩土物理力学参数是岩土工程设计及施工的主要依据。为得到更符合实际的岩土力学参数,研究提出了一种更加快捷准确的参数确定方法,即基于支持向量机(SVM)的位移反分析法。基于发展于自然仿生学的群智能算法-灰狼算法(GWO),结合差分进化算法(DE)的交叉变异操作对灰狼算法进行进化,得到一种差分进化灰狼混合优化算法(DEGWO),用其对支持向量机参数进行优化后反演出岩土力学参数。结合昆明某地铁隧道项目,采用Midas/GTS有限元软件构建模拟隧道施工的三维仿真模型。以某段隧道顶地表实测沉降数据为依据,用差分进化灰狼混合算法优化后的支持向量机模型反演岩体力学参数,并据反演参数及地勘报告建议参数计算得出的、Peck法计算的与实际地表监测的沉降值进行对比分析,结果表明:据反分析得出的参数计算的地表沉降值与实测值基本吻合,另外两种方法的计算值与实测值相差较大。通过以上分析表明本方法合理可行,反演出参数合理,用其进行计算的结果准确更符合实际,本方法能为岩土力学参数的获取、校核提供新的途径。Abstract: The geotechnical mechanical parameters are the main basis for geotechnical engineering design and construction.In order to obtain the geotechnical parameter information that is more in line with the actual situation, a displacement back analysis method based on the support vector machines, faster and more accurate parameter determination method, is proposed.Based on the grey wolf algorithm, a swarm intelligence algorithm developed in nature bionics, and combined with the crossover mutation operation of the differential evolutionary algorithm, the grey wolf algorithm is evolved, and the hybrid grey wolf optimization algorithm is obtained, which is used to reverse the geotechnical mechanical parameters after optimization of the support vector machine parameters.Based on the subway tunnel project in Kunming, the Midas/GTS finite element is used to establish a three-dimensional simulation model to simulate the tunnel construction process.Based on the measured surface deformation of the top section of a tunnel, the support vector machine model optimized by the hybrid differential evolution grey wolf algorithm is used to invert the mechanical parameters of rock mass.The settlements calculated by the back analysis method and the traditional Peck formula method are compared with the meas surface ones.The results show that the calculated surface settlements based on the back analysis are basically consistent with the measured ones, and the calculated values by the other two methods differ greatly from the measured ones.The above analysis shows that the proposed method is reasonable and feasible, the reverse performance parameters are reasonable, and the calculated results are more accurate and in line with the reality.The proposed method can provide a new way for the acquisition and verification of the parameters of rock and soil mechanics.