مطالعه و مدل‌سازي اثرات همبسته‌‌ي هيدرومكانيك در علل و مراحل خرابي كتيبه‌ي بيستون

Study and Modeling of Hydromechanical Effects on The Bisotun Epigraph Damaging Process

كتيبه‌ي بيستون يكي از مهم‌ترين آثار باستاني با قدمت 2500 تا 2600 سال است، كه در فاصله‌ي حدود 30 كيلومتري از كرمانشاه و تحت عوامل مختلف مخرب از جمله‌ جريان آب سطحي، انحلال ناشي از آب زيرزميني، هوازدگي، و ناپايداري بلوك‌ها قرار گرفته است. با توجه به اثر مهم جريان آب روي تخريب‌ها، اثرات هيدورمكانيكي روي كتيبه‌ي بيستون مد نظر است. رفتار همبسته‌ي هيدرومكانيكي توده‌ي سنگ به پارامترهاي مختلفي بستگي دارد، كه از آن جمله مي‌توان به شرايط تنش، مدول كشساني سنگ‌، سختي برشي و عمودي درزه، و اتساع درزه اشاره كرد، كه در اين مطالعه مركز توجه قرار گرفته‌اند. همچنين نتايج اين مطالعه نشان مي‌دهد كه ناهمگني‌، يكي از مهم‌ترين عوامل موثر روي خواص هيدروليكي و مكانيكي توده‌ي سنگ است. ضمناً چگالي ترك، مشخصات مكانيكي، و شرايط تنش از ديگر عوامل مهم هستند.

Bisotun epigraph is one of the most important traditional monuments of Hakhamaneshi Period with 2500 to 2600 years old which is located 30km far from Kermanshah.This epigraph has been subjected to various damaging factors, such as surface erosion due to water flow, ground water dissolution, weathering and rock block instability. Regarding to important role of water flow on damages, hydromechanical effects on the bisotun epigraph have been studied in this paper. Rock mass hydromechanical coupling behavior depends on various parameters such as stress conditions, rock modulus of elasticity, joint shear and normal stiffnesses and joint dilation which have been in center of this study. According to the results of this study, heterogeneity is one of the most significant factors on hydraulic and mechanical properties of the rock mass, also, fracture density, mechanical properties and stress conditions are another significant factors. One of the subjects which is studied and discussed in this paper is study on the best method to improve the fractures and cracks around the epigraph. According to the investigations the best method to improve the fractures is injection. In this regard hydromechanical coupling behavior related to the boreholes injection is studied. According to the importance and historical value of this epigraph, injection performance into the rock mass around the epigraph must be done with high quality and accuracy. One of the most important injection factors in this project is pressure due to injection which must be fully under control and its value must be evaluated by the numerical analysis because high injection pressure causes serious damages to this historical epigraph. In this regard hydromechanical behavior due to injection is studied in this paper and specifications and limitations of injection pressure are evaluated. One of the basic discussions which is evaluated in this paper is control of injection pressure in the range such that prevent of hydraulic fracturing. In the last part of the paper is tried to evaluate and study on the hydromechanical behavior due to injection such that hydraulic fracturing does not happen.