| The "8.8 Earthquake" caused huge damage to Jiuzhaigou located in the core area of the earthquake.Due to the earthquake,travertine hills and travertine dams collapsed or shattered in the special environment of Jiuzhaigou after hundreds of thousands of years.Under the influence of natural camps,it is easy to cause the instability and damage of quake-damped dams or travertine hills.The specific travertine will be degraded and lost,the travertine landscape will gradually fade,and even the biodiversity in the region will decline and natural evolution.Tend to swamp.Timely manual intervention is of great significance for the deposition of travertine in the protected area,restoration of damaged landscapes,and biodiversity.At present,mainly focusing on the protection and restoration of rock cultural relics or earthen sites,and the reinforcement materials are mostly cement and resin-based chemical materials.Based on the restoration concept of the World Natural Heritage Site with “mainly natural restoration,supplemented by manual intervention ”,Combining traditional wisdom with modern material science to develop modified glutinous rice mortar materials has improved the shortcomings of the traditional glutinous rice mortar reinforced soil,such as easy shrinkage,long setting time and low early strength.According to the above problems,the single-factor test was used to study the workability and rheological properties of the modified glutinous rice mortar,and the physical-mechanical properties of the reinforced soil by the cement-solid ratio,gypsum content,and travertine content were discussed.the research content and results obtained are as follows:(1)The degree of gelatinization of glutinous rice gum has a great influence on the properties of modified glutinous rice mortar,using viscosity as an indicator to measure the degree of gelatinization of glutinous rice glue,the changes of plastic viscosity and apparent viscosity with the heating temperature and holding time of glutinous rice glue are obtained.The heating temperature of glutinous rice glue reaches 80-90 and is kept at 90 for 40-60 minutes.It makes the glutinous rice glue more gelatinized,and it is found that the amylopectin in the glutinous rice glue can induce the formation of calcite.(2)In order to explore the effect of the modified glutinous rice mortar composition changes on the modified waxy rice mortar’s workability and rheological properties,the univariate test method was used to study the changes in the cement-solid ratio,gypsum content,additive content,and glutinous rice glue concentration.The influence law of setting time and fluidity of modified glutinous rice mortar material.It is found that the setting time of 2.5% glutinous rice glue shows a better effect,and the addition of 0.7%additive can make the slurry have better fluidity.The increase in the ratio of glue to solid and the decrease in the amount of gypsum will both The pumping period and the setting time are prolonged;using an Anton Paar rotary rheometer to study the rheological properties of the slurry with different components,modified glutinous rice mortar is a composite fluid of Bingham fluid and pseudoplastic fluid,and the modified waxy rice mortar shows a certain degree Thixotropic behavior.(3)In order to study the influence of composition changes on the strength of modified glutinous rice mortar stones and the physical and strength characteristics of reinforced travertine clay,the cement-solid ratio and gypsum content were changed to analyze the strength changes of modified glutinous rice mortar stones by changing the cement-solid ratio,The amount of gypsum and the amount of travertine soil are used to test the water absorption rate,density,harmony(color difference,heavy metal ion detection of the leaching solution of the reinforced soil)and unconfined compressive strength and flexural strength of the reinforced soil.When the cement-solid ratio increases,the density of the reinforced travertine clay decreases,the water absorption rate increases,and the color difference from the original travertine clay gradually increases;the increase in the amount of gypsum increases the density of the reinforced travertine clay,the density increases,and the water absorption The rate is reduced;the content of travertine is more than 50%,the density of reinforced travertine is obviously reduced,and the water absorption rate is obviously increased.The heavy metal ion detection of the leaching solution of the reinforced soil found that the leaching solution had no effect on the surrounding water body.Reinforced travertine clay has lower strength than modified glutinous rice mortar stones.The smaller the cement-solid ratio,the higher the amount of gypsum in a certain range,the higher the strength of modified glutinous rice mortar stone body and reinforced travertine,the lower the amount of travertine,the unconfined compressive strength and flexural strength of the reinforced travertine The larger,the stronger the resistance to deformation.(4)In order to study the mechanism of modified travertine clay reinforced by modified glutinous rice mortar,a micro-analysis of the reinforced travertine soil was carried out.Modified glutinous rice mortar wrapped and cemented the travertine particles and interspersed into the porous travertine particles,which reduced The pore structure of travertine clay enhances the strength of reinforced travertine clay.The travertine clay particles not only serve as aggregates,but also provide a stable carrier for the later carbonization to form calcite.The composition test of the reinforced travertine clay is carried out to improve the strength of the reinforced travertine clay.The essence is the improvement of the pore structure of the reinforced travertine clay by the calcite crystals and gypsum dihydrate crystals formed by the modified glutinous rice mortar.(5)Based on the experimental research project of the protection and cultivation of the Spark Sea in the Jiuzhaigou World Natural Heritage,the modified glutinous rice mortar and travertine soil were used to fill and repair the surface cracks of the earthquake-damaged travertine dam to achieve the harmony between the crack filling body and surrounding soil.The results of coring and pressurized water tests of the modified glutinous rice mortar material after curtain grouting show that the modified glutinous rice mortar can effectively improve the physical and mechanical properties of the reinforced travertine and reduce the permeability of the original formation.After the residual dam is grouted and reinforced,the deformation monitoring and seepage pressure monitoring in the reinforced area have been kept in a constant state for a period of time in the water storage,which can meet the design needs. |
PDF Full Text Request