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1. introduction because of construction technology, the heterogeneity of concrete material, and the temperature control of mass concrete, the concrete dam may exhibit the phenomenon of joints, especially at the heel of the dam. hydraulic fracturing sometimes occurs on the upstream surface under the action of high permeability water pressure for high concrete dams over 200 m. as the leakage channel formed by the fracturing failure is difficult to be blocked, it often needs to be caved out for overhaul, resulting in significant economic losses. for example, the dvorak concrete gravity dam in the united states, 219 m high, experienced improper temperature control measures during construction. consequently, the dam surface produced many cracks. seven years after the operation of the dam with water storage reaching the design maximum level, the dam cracks suddenly increased, with a crack depth of 50 m and an open width of 2.5 mm, causing approximately 483 l/s water seepage. then water level was then lowered to seal the hydraulic split crack. the movement of pressurized water in the microcrack imposes surface force load on the crack, resulting in the splitting force, equivalent to the "wedging" effect of a wedge, and accelerates the propagation and penetration of concrete microcracks (wang and li 2006a, 2006b). the resistance of external water penetrating into the concrete through the surface crack decreases, which promotes the water
بر اساس سیستم بارگذاری فشار آب با نفوذپذیری بالا که خود توسعه یافته است، خواص فیزیکی و مکانیکی و تکامل ساختار منافذ تحت فشارهای مختلف آب با نفوذپذیری بالا مورد بررسی قرار گرفت. هدف از این مطالعه آشکار کردن مکانیسم آسیب میکروسکوپی بتن در معرض فشارهای آب با نفوذپذیری بالا است. نتایج نشان می دهد که با افزایش فشار آب در شرایط مختلف نفوذپذیری بالا، محتوای آب داخلی افزایش می یابد. علاوه بر این، هرچه بالاتر باشد
