实测地质剖面中地层真厚度计算公式的修正

Correction of the Calculation Formula of Stratum True Thickness in the Measured Geological Section

摘要:

地层真厚度列氏公式被广大地质工作者所接受和使用，但仍存在诸多问题。从实际情况出发推导了地层厚度计算公式、分析了地层厚度取值范围和角度误差影响、讨论了“0值”、“负值”、“负厚度”等问题，并以实例进行了验证，得到以下认识： ①列氏公式只包含了两种野外实测情况，漏掉了一种野外实测情况，文中修正了地层厚度计算公式。②地层厚度F值范围为0~1， F值在三种野外测量情况下分别具有不同的变化特征，但均在地层倾向与测绳经过的地面坡向近垂直时取得最大值，均在地层倾向与测绳经过的地面坡向近平行时取得最小值。③真倾角、坡角、导线方位与地层走向之间锐夹角的误差影响在三种野外情况下分别具有不同的变化特征，但真倾角与坡角误差均在地层倾向与测绳经过的地面坡向近平行时对厚度计算影响最大，同时导线方位与地层走向锐夹角均在锐夹角小时对地层厚度影响大。④导线是平移导线时，地层厚度才为0；负厚度概念是在特殊的列氏改进公式中才具有意义，只表明导线由上层面到下层面；列式公式计算的负值是因为缺失一种野外实测情况造成的，负值不等于负厚度；修正的地层厚度公式计算值全为正值，符合客观实际，可结合构造分析用于计算地层总厚度。以上认识对于野外实测剖面选择、导线方位选择、室内地层厚度和总厚度计算具有指导作用，对于基于地层认识的科学研究和生产具有重要价值。

Abstract:

The леоновский’s stratum true thickness formula is widely accepted and used by lots of geologists, but some problems still exist. Based on the actual situation, the calculation formula of stratum thickness was deduced, the range of the stratum thickness value and the influence of angle error were analyzed, and the problems of zero data, negative data and negative thickness of the stratum thickness were discussed. Finally, the case study was carried out to verify it. The results are obtained as follows: ①the леоновский’s formula only contains two kinds of field measurement and omits one kind of field measurement, so the calculation formula of stratum thickness is corrected; ②the range of F-data of stratum thickness is 0~1,and the F-data has different variation characteristics in three field survey situations respectively, but the maximum values are all obtained when the stratum dip direction is nearly vertical to the ground slope where the measure line passes, and the minimum values are all obtained when the stratum dip direction is nearly parallel to the ground slope where the measure line passes; ③the error influence of true dip angle, slope angle as well as the acute angle between the guiding line direction and the stratum strike has different variation characteristics in three field conditions, but both the true dip angle and the slope angle error have the greatest influence on the thickness calculation when the stratum trend is nearly parallel to the ground slope direction where the measure line passes, meanwhile, the acute angle between the guiding line direction and the stratum strike has the greatest influence on the stratum thickness when the acute angle is smallest; ④When the measure line is the translation line, the stratum thickness is zero; the concept of the negative stratum thickness only has its sense in the modified form of леоновский’s formula, which just indicates that the measure line crosses from the upper stratum surface to the lower stratum surface; the negative data of the calculation using the леоновский’s formula is caused by that the леоновский’s formula lacks one kind of field measurement, and the negative data isn’t equal to the negative thickness; the calculated values of the corrected formula are all positive values, which are in line with the objective reality, meanwhile it can be used to calculate the total stratum thickness combining with the structural analysis. The above knowledge has a guiding role in the selection of field measured profile and guiding line direction as well as the calculation of indoor stratum thickness and total thickness, and has an important value in the scientific research and production based on stratigraphic knowledge.