| Rockfall disasters are common natural disasters in southwestern my country,which are characterized by strong suddenness,randomness,damage and difficulty in prevention and control.Once the rockfall disaster occurs,it will endanger people’s life and property safety and cause great economic losses.Therefore,it is extremely important to effectively prevent and control the rockfall disaster.Reinforced soil retaining walls have been gradually applied in rockfall disaster prevention and control due to their excellent impact resistance,excellent rockfall interception effect,strong economy and low repair difficulty.At present,the research on the reinforced soil retaining wall under the impact of rockfall mainly stays on the deformation characteristics and dynamic response analysis of the retaining wall under the single impact,and there are few studies on the evaluation methods,failure characteristics,failure mode and damage of reinforced soil retaining wall under the multiple rockfall impacts.Therefore,in order to guide the design and engineering application of the reinforced soil retaining wall,it is necessary to carry out research on the failure process and damage assessment of the reinforced soil retaining wall under the impact of multiple rockfalls.In this paper,model tests of reinforced soil retaining walls under rockfall impact with different impact energies are designed and carried out.Combined with theoretical analysis and numerical simulation,the failure process and damage assessment methods of reinforced soil retaining walls under rockfall impact are explored.The main contents include:（1）Design and carry out model test of reinforced soil retaining wall under rockfall impact.Through the test of rockfall impacting the reinforced soil retaining wall with different impact energy,the deformation law,the impact range and the damage characteristics of the reinforced soil retaining wall are obtained,the damage stages and judgment indicators of the reinforced soil retaining wall are summarized.The failure mechanism of reinforced soil retaining wall and the mechanism of reinforcement are analyzed.The test results show that the reinforced soil retaining wall has the failure characteristics of cavity in wall,protruding on the back of wall,reinforced inclusion slip and overall inclination of the reinforced soil retaining wall under the impact.After the rock hits the reinforced soil retaining wall and overshoots,the reinforced soil retaining stone wall failed and damaged.According to the failure characteristics of the reinforced soil retaining wall,the failure process of the reinforced soil retaining wall under impact can be divided into three stages:（1）impact compaction;（2）slip and tilt;（3）overtop and failure.The experimental study shows that the impact failure process of the reinforced soil retaining wall is a slow process of gradual accumulation of deformation and sliding and tilting of the reinforced soil retaining wall.（2）Research on the deformation calculation and damage assessment method of the reinforced soil retaining wall under the impact of rockfall.In this paper,based on the failure process of the model test of the reinforced soil retaining wall,the proposed values for the distribution of the impact energy dissipation in each stage of the failure process of the reinforced soil retaining wall under the rockfall impact are proposed.Combined with the energy method,a calculation method for the impact deformation of the reinforced soil retaining wall considering the change of the soil modulus is proposed,and the damage factor is introduced to propose an impact damage assessment method for the reinforced soil retaining wall.The research shows that the impact energy of rockfall is mainly consumed by soil compaction deformation at the impact point and reinforcement friction.It is suggested that the ratio of soil compaction deformation energy consumption and reinforcement friction energy consumption in the first stage of failure isE0 1:E02≥91:,the ratio of soil compaction deformation energy consumption to reinforcement friction energy consumption in the second stage is91:≥E0 1:E02≥7 3:,and the ratio of soil compaction deformation energy consumption to reinforcement friction energy consumption in the third stage is7 3:≥E0 1:E02≥5 5:.The damage assessment method using the deformation inclination of the reinforced soil retaining wall as an evaluation index has certain guiding significance for the damage assessment of the reinforced soil retaining wall under the impact of multiple rockfalls.（3）Carry out the numerical simulation research and analyze the deformation law,damage situation and failure process of the reinforced soil retaining wall under the impact of rockfall under various working conditions.The failure process and failure form of the reinforced soil retaining wall under the impact of different impact point positions and different volumes of rock are explored,and the failure mechanism of the reinforced soil retaining wall and the action mechanism of the reinforcement are analyzed based on the model test results.The numerical simulation results show that the location of the rockfall impact point and the size of the impact body have a significant impact on the damage degree and the damage process of the reinforced soil retaining wall.Under the same impact energy,the higher of the impact point position or the larger of the volume of impact body,the more serious the damage to the reinforced soil retaining wall,and the more likely the rock over the top of the reinforced soil retaining wall.During the whole failure process of rockfall impact,the reinforcement acts as a net pocket and resists the impact force of the rockfall through its own tensile performance,which maintains the overall integrity and improves the deformation resistance of the reinforced soil retaining wall. |
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