Intrusion behaviour of tree roots to rock mass caused by geologic structure

Abstract

Tree root intrusion to rock mass plays important effect to weathering and to deformation of rock mass. The phenomena that the tree roots intrude to the opened dis-continuity planes in rock mass, can be commonly recognized. Therefore, the conditions of discontinuity planes which is one of basic conditions controlling intrusion of root to rock mass were investigated. The results of investigation are as follows. 1) The tree roots will intrude to rock mass along to existing discontinuity planes such as the bedding planes and the conjugate planes. 2) The roots intruding cracks coinciding with stratum of opposite dip will not give stress to rock mass because the maximum diameter of roots is equal or less to the width of cracks. 3) If the roots intrude to confined discontinuity planes, the roots will give stress to rock mass, because the maximum diameter of roots exceed the width of cracks.