中文摘要：

为了提高垂直电测深二维反演的收敛速度和反演精度，给出了利用直接反演公式确定初始模型的方法。在直接反演过程中，通过综合利用三次样条求导法、五点求导法和列维尔插值计算电测深曲线在每个极距处的梯度，并对直接反演结果进行深度校正，获得了更准确的反演结果，为二维反演提供了较好的初始模型。通过对模拟和实测电测深数据进行反演试算，验证了采用直接反演法给定非均匀初始模型的可行性和有效性。

英文摘要：

In order to improve the convergence rate and inversion precision in 2D inversion of vertical electrical sounding, to give the initial model of 2D inversion applying the formula of approximate inversion is put forward. During the approximate inversion, the accurate inversion result is got by comprehensive utilizing cubic spline method, five points method and Neville interpolation to compute the gradient values of every electrode spacing of electrical sounding curve and modifying the depth of approximate inversion result, providing good initial model for the 2D inversion. The feasibility and effectiveness of the non-uniform initial model by approximate inversion method to 2D inversion are verified through inverting the simulated and measured vertical electrical sounding data.