Research On Regional Soil Theory And Characterization Methods

Whether from the perspective of researchers or engineers,it has been recognized that the engineering and mechanical properties of soil have regional characteristics.It is also believed that personalized design of geotechnical engineering considering regional characteristics is a key development direction in the future.However,research in this area is currently mainly at the qualitative stage.The methods of characterizing regional soil characteristics using apparent indicators such as geological age,particle shape,terrain and geomorphology are difficult to establish quantitative relationships with soil mechanics or engineering characteristics within the scope of geotechnical design requirements,and can only serve as primary qualitative indicators for regional soil classification.From the perspective of geotechnical engineering design,the core issue of the theory of regional soil characteristics is how to quantitatively characterize and characterize the regional characteristics of soil engineering and mechanical properties using conventional soil mechanics or engineering parameters.However,there is currently a gap in research results in this field both domestically and internationally.This paper is based on the development needs of geotechnical engineering,exploring the theory of regional soil characteristics,and completing the construction of the core theory of regional soil characteristics in a quantitative and engineering manner.It lays a theoretical foundation for the analysis of the correlation between the characterization of regional soil characteristics and soil properties in different regions,as well as personalized design of geotechnical engineering considering regional soil characteristics in the future.The main research work of this paper is as follows:(1)In response to the issue of which parameters and functions can characterize and characterize the regional characteristics of soil engineering and mechanical properties,the concepts of dual control parameters and regional soil characteristic function are proposed by analyzing the classic constitutive models of soil mechanics and soil dynamics.At the same time,criteria for constructing regional soil characteristic function are established,including attribute requirements such as controllability,universality,completeness,in-situ consistency,operability,and existence.(2)The existence of soil characteristic functions in actual regions is studied.A database of N-Vs relationship curves for existing regional soils worldwide is constructed,the principle that N-Vs relationship curves can be used as a regional soil characteristic function is demonstrated,the identity of curves in different regions is studied,and the existence of N-Vs characteristic functions for conventional sandy and clay regional soils is demonstrated.(3)The stability and convergence of N-Vs characteristic functions are demonstrated.Using random analysis of measured data,array thresholds for constructing N-Vs characteristic functions with different accuracies are proposed,and the answer to the number of N-Vs arrays required to construct N-Vs function relationships in a region in a statistical sense is given,forming a scientific construction method for N-Vs characteristic function.(4)The differences of existing N-Vs characteristic functions in different regions of the world are studied and a simplified evaluation method for the differences of N-Vs characteristic functions between any two regions is proposed.A quantitative understanding of the sources and degrees of differences in the N-Vs function relationship under sand and clay in different regions of the world are obtained.Using the two coefficients of the N-Vs characteristic function in different regions as calculation parameters,a N-Vs characteristic function difference evaluation method that can be directly applied in engineering is developed.(5)In response to the problem of liquefaction discrimination,based on the proposed theory of regional soil characteristics,a conversion method for liquefaction discrimination for different regions is established.Based on the N-Vs characteristic function,the implementation steps of the conversion method are established,and the reliability of the method is verified using liquefaction data from China.The establishment of the conversion method of liquefaction discrimination in different regions will lay a foundation for the reasonableness evaluation of the national standard of liquefaction discrimination derived from local data in other regions and the establishment of the revised formula.