Study On Static And Dynamic Characteristics And Structure Model Of Saturated Red Clay

In China's Yungui Plateau and Minnan and other areas are distributed a large area of red clay,with the steady development of these areas,the transportation network is also slowly perfecting,red clay land base under construction or has been built railways,roads and other major projects.The static load effect of the embankment and the long-term traffic cycle load effect caused the ground soil body to produce a large accumulation deformation,resulting in a significant decrease in the strength of the soil body,which makes the foundation of the structure easy to produce excessive deformation or instability,which is a major threat to the national economy and life safety.Therefore,improving the long-term service performance of traffic engineering is the key to solve this threat,so it is necessary to carry out the study of static power characteristics of saturated red clay.After the treatment of the original soil,it is made into a high-quality remodeled soil sample,in order to study the dynamic force characteristics of red clay under different conditions,through the GDS dynamic triax meter,the reconstruction of saturated red clay specimen stoic test research,the main completion of the following work:1.Taking into account the long-term dynamic characteristics of saturated red clay under traffic load,a three-axis test of one-way vibration of 1000 times was carried out under different circumference pressure and different cycle stress ratios.The effects of different solid-crust circumference pressure and different water content on the shear strength,stress-strain relationship,hole pressure-strain relationship and effective stress path development are studied,and the linear relationship between solid-junction envelope pressure and anti-shear strength and the nonlinear relationship between moisture and anti-shear strength are established.The hole pressure expression of saturated red clay specimen under different stress paths on the p-q plane is established according to the expression of the normal perforated pressure under hole pressure relationship.2.In view of the long-term characteristics of saturated red clay under traffic load,a one-way vibration three-axis test of 1000 times under different perforated pressure and different cycle stress ratio was carried out.The effects of different perforated and circulating stress ratios on saturated red clay strain and hole pressure development and effective stress path,the evolution process of stress-strain hysteresis,the accumulation of rebound strain and the softening of the rebound ingresss of the spring-return pattern under different conditions were studied,and the predictive equation of the number of cycles with the cumulative strain under different cycle stress ratios was established.The model parameters in the prediction formula are determined,and the threshold cycle stress ratio of red clay in southern Fujian is 0.01-0.05 and the critical cycle stress ratio is about 0.4.3.Based on the dynamic structure characteristics of saturated red clay under the action of traffic load,the modified Iwan model suitable for red clay in southern Fujian is established,based on the Iwan model,and the long-term accumulation of strain is considered.According to the static test results made in this paper,the initial backbone curve and model parameters of the Iwan model are modified,and the correctness and applicability of the model are verified by the comparison of the measured and predicted values.