Experimental Study On Dynamic Strength Of Saturated With Fine Gravel Sand

Sand liquefaction is one of the most significant form of damage, it is always a hot issue for sc holars at home and abroad. Effect of liquefaction of saturated sand by many factors, including soil c onditions, load conditions, burial conditions, drainage conditions, soil initial stress state and stress hi story etc.Besides pure sand in the nature, but also abundant conglomeratic sandy soil, especially the Xi nJiang region. Head of tuen mun river basin in Xinjiang, the author of this paper was carried outin a construction site containing fine gravel sand group of dynamic triaxial test, and the dynamic strength of saturated with fine gravel sand and development rule of pore pressure is analyzed. Dr aw the following conclusions:Ambient pressure and consolidation stress ratio on saturated fine gravel sand had a great effec t on dynamic strength. The surrounding pressure and consolidation stress ratio, the greater the satu ration intensity, the greater the containing fine gravel sand. Vibration frequency and relative densityof saturated fine gravel sand the influence of dynamic strength is more obvious. Vibration freque ncy, the greater the relative density, the greater the dynamic strength of saturated with fine gravel sand.The dynamic stress amplitude has signif icant effect on the development of dynamic pore press ure of saturated sand bearing sand soil. The bigger the dynamic stress amplitude, the faster the pr essure rise, the more the ratio of the dynamic pore pressure, the easier the damage of the soil. Th e influence of relative density and vibration frequency on the development of dynamic pore pressu re of saturated sand bearing sand is obvious. Higher relative density, dynamic pore pressure rises more slowly, dynamic pore pressure ratio is low, soil is not easy to be destroyed; vibration freque ncy, dynamic pore pressure rise faster, dynamic pore pressure is higher than the occurrence of da mage to the shorter time, the soil is easy to destroy.The effect of fine gravel content on the dynamic strength and dynamic pore pressure of satur ated sand soil is notable.. Under different confining pressures, different vibration frequencies, differe nt relative density and different consolidation stress ratio, the dynamic strength of saturated sand s oil increases with the increase of fine gravel content. The more the fine gravel content, the slower the pore pressure, the smaller the dynamic pore pressure ratio, the longer the damage time.If the same condition, the consolidation stress ratio, the greater the dynamic pore pressure of the saturated with fine gravel sand value, the more difficult it is to achieve the confining pres surevalue. When the consolidation stress ratio is 1.0,the rate of pore water pressure along with the i ncrease of the ratio of dynamic stress is accelerated, the easier the soil damage; When the consoli dation stress ratio is 1.5 and 2.0, the rate significantly less than the constant pressure consolidation state of pore water pressure, when achieve dynamic strain damage condition, pore pressure can’t r ise to confining pressure. When the consolidation stress ratio is 1, the pore pressure rise to 0.85 ti mes the confining pressure; When the consolidation stress ratio is 2.0, the pore pressure rise to 0.7 times the confining pressure. According to different consolidation ratio of the vibration of the sa turated with fine gravel sand when pore pressure ratio curve, choose three different pore pressure stress model fitting. Fitting results show that the improved Zhang jianmin type A curve fitting effe ct is better than Zhang jianmin A model, but these two models are not hyperbolic model fitting ef fect is good.