节理平均迹长与统计窗选位关联性分析  

RELATIONSHIP BETWEEN MEAN TRACE LENGTH OF JOINTS AND LOCATION OF SAMPLING WINDOW

作　　者：申艳军[1,2] 徐光黎[1,2] 董家兴[1,2] 朱可俊[3] 

机构地区：[1]中国地质大学岩土钻掘与防护教育部工程研究中心,湖北武汉430074 [2]中国地质大学工程学院,湖北武汉430074 [3]中国水电工程顾问集团成都勘测设计研究院,四川成都610072

出　　处：《岩石力学与工程学报》2011年第3期596-602,共7页Chinese Journal of Rock Mechanics and Engineering

摘　　要：目前常用的统计窗迹长估算方法多假定节理中心在各向服从均匀分布,即认为统计窗的布置点位对平均迹长估算结果无影响。而实际上节理作为漫长地质演化过程的产物,受多期地质建造、构造综合作用,使得其形态及规模已发生较大的改变,呈现典型的地质韵律特征,若随机布置统计窗点位将会产生截然不同的迹长估算结果。为研究节理迹长与统计窗选位的关联性,以大岗山水电站地下主厂房区为例,首先对厂房区下游边墙节理组进行地质演化过程分析,确定厂房区优势节理组为辉绿岩脉及其节理影响带。接着以岩脉β81及其影响带为代表,对其发育地质韵律特征予以详细研究,藉此提出统计窗布置点位、尺寸及估算方法建议。最后采用5种统计窗估算法对研究区各区段节理迹长进行对比分析。研究发现:节理估算迹长与统计窗选位存在较强的关联性,不同的节理发育特征及统计窗布置点位适合于不同的节理组迹长估算方法,在应用统计窗法估算节理迹长时,需充分考虑优势节理发育规律,合理选择统计窗位置,尽可能将不同类型的节理包含其中,使之同时体现切割、交接、包含3种关系,并选取适合于本统计窗的迹长估算方法。Now the assumed condition of common sampling window methods is that joint centers obey the uniform distribution,it means that the location of sampling windows has no effect on mean trace length of joints.Yet in fact,as products of the lengthy geological evolution,joints have been suffered from multiple geological formations and tectonic movements,shapes and scales have been changed largely;so their distributes display typical geological rhythm characteristics.If sampling windows are arranged at random,they will generate different mean trace length results.In order to find the relationship between mean trace length of joints and location of sampling window,taking the underground main powerhouse of Dagangshan hydropower station for example,firstly,the geological evolution rule of joints at its downstream wall was analyzed,and that diabase dikes and their influence areas were identified as the dominant joint sets,then choosing diabase dike β81 and its influence areas to research their geological rhythm characteristics in detail;based on their characteristics,these proposals about the locations,sizes and estimation methods of sampling windows for deciding mean trace length of joints are put forward.Finally,five kinds of methods are used to calculate and compare the estimation results of mean trace length in different sections.The results indicate that the mean trace length of joints has a strong relationship with the location of sampling window;different distribution characters of joints and different locations of sampling windows will lead to different calculated values.So when using sampling window methods,it is needed to adequately consider the development rules of objective joints,and assign the location of sampling window accurately in order to contain all kinds of joints as far as possible;the sampling window should include intersecting,transecting and contained traces synchronously;and the estimation method should be chosen adequately.

关 键 词：岩石力学 统计窗点位 平均迹长 优势节理组 地质韵律特征 关联性 

分 类 号：TU45[建筑科学—岩土工程]