用地质统计学计算土层相关尺度

ESTIMATION OF AUTOCORRELATION DISTANCE OF SOIL PROPERTIES BY USING GEOSTATISTICS

随机场理论可以用来模拟土工参数的空间变异性,而地质统计学也借助于随机场理论对自然资源进行估计、模拟和评价,很明显随机场理论是两类应用的共同理论基础,因而借助于发展较成熟的地质统计学理论估算土层相关尺度应是一条有效的途径。本文论述了该方法的理论基础,认为求取变差函数与求相关函数是等价的,建立并证明了八类理论变差函数与其相应的相关距离之间的解析关系,介绍了具体的计算步骤:计算实验变差函数、选择合适的理论变差函数模型、最优拟合实验变差函数、计算相关距离,以实例说明了实际步骤以及结果的有效性和实用性。

Random field theory is frequently employed to model spatial average soil properties, while since the 1960 ＇s geostatisties, based on random field theory, has become the most common method to estimate natural resources. It may be an efficient way to model soil spatial variabilities by using geostatistics. This paper presents a convenient procedure for estimating the scale of fluctuation of soil stratun by means of variogram. The procedure includes four steps： calculating experimental variogram from measured data, selecting a suitable theoretical variogram model, fitting the theoretical variogram model with the experimental variogram, taking the parameters obtained from the optimization of the theoretical model into the relationship between the range or asymptotic parameter a,, in geostatistics and the scale of fluctuation, δ. Eight typical expressiom between a, and δ are provided, and a practical example is presented for illustrating the methodology. It is concluded the new method is practicable, simple, and efficient when compared with previous methods.