地壳上部构造的球壳失稳模拟实验及力学分析

李四光早年曾提到过,在构造模拟实验中把曲率考虑进去,对大区域构造研究可能具有某些重要性。但这种实验的作法及意义,五十年来少有研究。当地壳曲率的实际重要性不明确时,由局部平面模拟结果无限制地外推到全球构造体系,无疑会产生误差。我国秦岭-昆仑纬向构造体系横跨40°左右,显然这里地壳不是弹性平板梁的受力状况,而是更接近于弹性薄壳。 实验表明这种推断是合理的。

MODEL EXPERIMENTS ON THE INSTABLE SPHERICAL SHELL OF THE UPPER CRUSTAL STRUCTURE AND ITS MECHANICAL ANALYSIS

A number of model experiments on the geological structure of upper crust were conducted in the light of the instability of the spherical thin shell,resulting in the display of the structural patterns more or less similar to that formulated by Li Siguang.The results reveal the intrinsic relationship between the rhombic tectonic framework and that patterns displayed in these experiments.The experiments illustrated in Photo (1) and (2) were made under the condition of body forces.The present author holds that the instability mechanism of the upper crust may very likely control to a certain extent the tectonic movements occurring in it.Therefore,the structural features of earth’s crust should not be neglected.The force generated by the effect of the earth rotation is probadly matchable with that causing the instability of earth’s crust.