南水北调西线工程雅砻江调水区横向构造的地质特征及成因机制

雅砻江调水区的横向构造按成因可分为两种，剪切成因的横向构造不具有区域规模，有明显的构造断面，其形成与北西向构造有密切关系，具有多期活动性，后期的复活多是继承性的，与北西向构造的交汇部位是孕震的重要地段．张性的横向构造具有典型的弥散性，由一组构造面断续分布的断层、褶皱、裂隙及相关地貌组合而成，但延伸规模较大，是一种典型的叠加性构造，形成于早第四纪；其形成是基底隐伏断裂在张或剪应力的作用下重新活动的结果，变形强度由下到上逐渐减弱，变形逐步扩散；横向构造的发育既有对南水北调工程不利的一面，也有其有利的一面

Geological features of transverse structuresin Yalongjang water-transferring region and its mechanics

Transverse structures can be classified into two kinds in Yalongjiang water-transferring region, namely sheared transverse structure and tension transverse structure. Sheared transverse structure extends with sharp interface at little regional scale. The formation of sheared transverse structure is more related to the activity of NW-structures, and with multiphase tectonic activity. Its succeeding activity usually is inherited. The intersected place of sheared transverse structure and NW-structure is the important earthquake-pregnant tectonic site. Tension transverse structure consist of a group of units assembled by faults, folds, fissures, and related land form. It extends at large scope in form of typical diffusive. Tension transverse structure is the classic superimposed structure and formed in early Quaternary. The genesis of transverse structure in Yalongjiang water-transferring region was the result from the newly activation of buried basement fault, and the deformational intensity became weaken from the base to cover. There are benefit factors to water-transferring project, also harmful to it.