تعیین شکل درزه‌ها در توده‌سنگ توسط شبیه‌سازی آماری

نوع مقاله: پژوهشی

نویسنده

دانشگاه یاسوج، دانشکده فنی و مهندسی- گروه عمران

10.29252/anm.7.13.27

چکیده

یکی از عوارض زمین‌شناسی بسیار مهم در تعیین مقاومت و پایداری توده‌سنگ‌ها موقعیت و آرایش درزه‌ها و شکستگی‌ها است. در اینجا شکل درزه شکل هندسی است که از جهت عمود بر سطوح درزه‌ها دیده می‌شود. در مورد شکل هندسی درزه‌ها اطلاعات زیادی وجود ندارد. بعضی از مراجع به صورت تقریبی شکل آنها را مربعی، مستطیلی، دایره‌ای و بیضوی ذکر کرده‌اند. به دلیل آن که معمولاً محل تقاطع صفحه یا رویه درزه با صفحه رخنمون سنگی به صورت یک پاره‌خط قابل رویت است، به سختی می‌توان شکل درزه‌ها را در رخنمون‌های سنگی مشاهده ‌نمود. در این تحقیق درزه‌های موازی که تشکیل سیستم درزه می‌دهند توسط شبیه‌سازی آماری و برای اشکال مختلف تولید گردیده‌اند. سپس با مطالعه چگونگی توزیع آماری درزه‌های شبیه‌سازی شده و مقایسه آن با توزیع آماری واقعی درزه‌ها در رخنمون سنگی می‌توان فرم و شکل درزه‌ها در توده‌سنگ را پیش‌بینی نمود. بررسی‌های حاصله نشان می‌دهند، توزیع آماری طول درزه‌ها‌ی شبیه‌سازی شده برای سیستم‌های درزه از توزیع‌های آماری رایج و کلاسیک توانی، لگاریتمی و پواسون پیروی نمی‌کند. طول درزه‌ها در واقع دارای توزیع پیچیده و اکثراً دارای چولگی به سمت چپ هستند.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

The Joint Shape Determination in Rock Mass by the Statistical Simulation

نویسنده [English]

  • Mehdi Zamani Lenjani
Yasouj University, Engineering and Technical Faculty, Civil Engineering Department
چکیده [English]

Summary
Geometry of joints or joint shapes is one of the geological characteristics, which is important for determining the strength and stability of rock mass.  Here joint shapes mean the geometric forms of joints when looking from the direction normal to the joint planes. There is not enough literature and references about the shape of the joints. Some of them consider approximately the joint shapes as square, rectangular, circular or even elliptical forms.  We usually observe the traces of joints as segments in rock outcrops but it is difficult to see their shapes in the outcrops of underground openings. In this research the parallel joints which form a joint set, are created by the statistical simulation for different joint shapes. Then by comparing the simulated joint distribution with the real joint set distribution from outcrop measurements, it is possible to predict the shape of joints in rock masses. The simulation results showed that the joint set distributions will not follow the classic statistical distributions such as logarithmic, power, exponential or Poisson. They are complex in nature and have a skewness to the left.
 
Introduction
One of the important parameters of discontinuities in rock mass is the shape and geometry of joints. The effects of joint shape and its geometry in rock mass resistance properties are defined by many rock mechanics and engineering geologist specialists. They assumed the shape of joints as square, rectangle, circular and elliptical features.
 
Methodology and Approaches
For determination the shape of joints in rock masses in this research the statistical engineering is applied. The joints and discontinuities are considered two-dimensional planes. Then by intersection of a random plane normal to the joint set planes the simulation of joints in outcrop were obtained. At the end by the distribution of the joints obtained from the simulation, one can determine the shape of the joints.
 
Results and Conclusions
The results showed that the joints with circular, uniform shapes and with the relative movements have the exponential distribution of trace length. But for nonuniform cases the distribution approaches the normal distribution. A uniform distribution was observed for the square or the diamond shape of the joints.

کلیدواژه‌ها [English]

  • joint set
  • rock outcrop
  • simulation
  • joint length
  • joint shape
  • instability
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