Fuzzy Appraising Method Investigation On Tectonic Stress Action Mode

The In-situ stress problem is an important investigation area of engineering geology, rockmechanics and relating disciplines. Tectonic Stress is an important constituent of groundstress. To study on tectonic stress, not only its magnitude should be determined, butalso its action mode and direction. Determining the action mode and direction oftectonic stress is an important basing for further initial in-situ stress field regresscalculating. Acknowledging the action mode and direction of tectonic stress hasreference merit in determining cave line, location and excavation mode. Now, theprecise analytical of tectonic stress can't be given due to many fuzzy influent factors. In this paper, the fuzzy comprehensive appraising method, base on actualmeasurement, is put forward to study the action form and combination scheme oftectonic stress. The entire possible action form and combination scheme of tectonicstress is determined by study on tectonic stress initial in-situ stress field. The finiteelement model is found basing on geology reconnaissance and survey data. Then, thestress of all possible action modes of tectonic stress is calculated with finite elementcomputer software by makes use of various tectonic stress combination form asboundary loading condition. The results of every gaging hole are reckoned in tectonicstress database. Founding the fuzzy subordinate function and comparing the actualsurvey in-situ stress vector with tectonic stress in database, the subordinate degrees ofvarious tectonic stress action forms and combination are educed. Analyzing with thesedegrees, the closest actual condition of tectonic stress action forms is got. The fuzzy comprehensive appraisal of tectonic stress action forms and combination isput forward base on fault information. The fault is universal existence in lithosome. To someextent, the fault information attributes the tectonic stress action forms and combination andis the need information to judge the direction of tectonic stress. According to therelations between the strike fault and the direction of tectonic stress, the subordinatedegree of each combination form of difference strike, whose appraisal factor set isstrike and comment set is load combination form of tectonic stress, is given. In theend, the most possible load combination form of tectonic stress, which belong to onearea, is comprehensively appraisal under the condition of known fault information. Analyzing with above method gets the closest actual condition solution. The result shows thatthe outcome of fuzzy comprehensive appraisal is more reliable and convince than judging withexperience. Therefore, the fuzzy comprehensively appraisal method is an effective meansin appraising the tectonic stress action form and combination and can be used inengineering practice.