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弹性波全波形反演方法是岩土工程领域中一种较新的无损检测手段,它综合运用响应波场的振幅、旅时、相位和频谱特种等波形信息,通过一定的数学反演方法,获取目标介质的物理力学参数,具有对介质模型精确刻画的潜力。将时域有限差分法结合完全匹配层吸收边界条件技术实现对弹性波波动方程数值模拟求解。然后将拟线性最优化法与随机搜索法相结合,发展了一种稳定、高效且适用于尺度较小(0.1~10 m)的时间域弹性波全波形反演方法,具有对初始模型依赖少,易收敛于全局最优解等优点。将弹性波全波形反演方法应用我国北方某住宅楼已建结构实体的复合地基承载力检测复核中,根据在该楼混凝土地下室底板上采集到响应波场,全波形反演方法计算获得地下室底板下部复合地基剪切波速剖面,进而通过经验公式获得复合地基综合承载力值,取得了良好的应用效果。
The full waveform inversion method of elastic wave is a relatively new nondestructive testing method in the geotechnical engineering field. It comprehensively uses waveform information such as the amplitude of the response wave field, travel time, phase and spectrum specialties, and through certain mathematical inversion methods, Obtaining the physical and mechanical parameters of the target medium has the potential to accurately characterize the media model. The time-domain finite difference method and the perfectly matched layer absorption boundary condition technique are used to solve the numerical simulation of the wave equation of elastic wave. Then combining the quasi-linear optimization method with the random search method, a full-wave time-domain elastic wave inversion method which is stable and efficient and suitable for small scale (0.1 ~ 10 m) is developed. It has the advantages of less reliance on the initial model, Easy to converge to the global optimal solution and so on. Applying the full waveform inversion method of elastic wave to the checking and checking of bearing capacity of composite foundations of a residential building in the north of China, according to the response wave field collected on the floor of the concrete basement of the building and the full waveform inversion method, the floor of the basement Lower composite foundation shear wave velocity profile, and then through the empirical formula to obtain the composite foundation bearing capacity, and achieved good results.