Extension Comprehensive Evaluation Method For Bearing Capacity Of Old Cohesive Soil Foundation

All kinds of engineering construction are inseparable from underground rock and soil.Due to the complexity of the rock and soil,the corresponding foundation bearing capacity is also different.Therefore,if the foundation bearing capacity is judged incorrectly in the construction of the project,it is likely to cause serious safety accidents,and cause significant economic losses or even life safety..Therefore,how to determine the foundation bearing capacity of various types of rock and soil that meets the requirements of project construction is extremely important.It is a very important technical work,which is related to the safety and economic benefits of the project.Old cohesive soil is a geological environment often encountered in engineering construction.At present,there are two main methods used to determine the bearing capacity of old cohesive soil foundations: one is to determine the physical and mechanical properties of the soil measured by indoor geotechnical tests;It is calculated by using empirical formulas based on the static cone penetration index and standard penetration test index obtained by the on-site in-situ test,or the foundation bearing capacity of the test site can be directly obtained through the on-site load test.Among them,the on-site load test is also the most reliable in-situ test.testing method.In the Changchun area,the original soil samples of the old cohesive soil were selected,and the factors affecting the bearing capacity of the old cohesive soil foundation were obtained through indoor geotechnical tests.The theory of extenics was introduced into the evaluation of the bearing capacity of the old cohesive soil foundation.These factors are based on matter-element theory,correlation function calculations and extension set theory,and an extension evaluation model for the bearing capacity of old cohesive soil foundations is established through the extension evaluation method,and the evaluation results are verified by field load tests.A grading standard suitable for the bearing capacity of the old cohesive soil foundation is obtained.The method is more rigorous in theory.In the evaluation process,the natural moisture content,mass density,compressive modulus,void ratio,liquidity index,cone tip resistance and other factors have been comprehensively considered for the bearing capacity of the old clay foundation.Impact and conduct comprehensive evaluation.The approximate range of the bearing capacity of the old cohesive soil foundation corresponding to the evaluation grade: Grade I and Grade Ⅱ≥450k Pa,Grade III is350-450 k Pa,Grade IV and Grade V≤350k Pa.The division of evaluation grades still needs to rely on a large amount of statistical data.In the future,more work in this area should be carried out to accumulate data and experience to make it more perfect.The results of this paper also provide a reference for the classification of the bearing capacity of the old cohesive soil foundation in other regions.