Rock and Soil Mechanics 

About: Rock and Soil Mechanics is an academic journal. The journal publishes majorly in the area(s): Pile & Rock mass classification. It has an ISSN identifier of 1000-7598. Over the lifetime, 4943 publications have been published receiving 16400 citations.

On stress state variables of unsaturated soils

Abstract: Based on thermodynamics and stress theory of continuum mechanics,a series of stress state variables of unsaturated soils,which covered all stress state variables used in literature,are deduced from the equilibrium equation of soil skeleton.It is shown that there are more than five combinations of stress state variables for unsaturated soils,most of which are related to physical properties such as void ratio and degree of saturation.Stress state variables should have dimensions of stress,while void ratio,degree of saturation and their combination could not be regarded as stress state variables.Both the simplified Bishop's effective stress equation and the Fredlund's two stress state variables are simplified forms of stress state variables.The influence of void ratio is not included in the simplified Bishop's effective stress equation,while the dependence on void ratio and degree of saturation are neglected in the Fredlund's two stress state variables.When choosing stress state variables for unsaturated soils,rationality in theory and convenience in application as well as correctness in logic should be taken into account.

An anisotropic elastoplastic model for soft clays

Abstract: The modified Cam-Clay model is only applicable for isotropically consolidated soft clay;and it cannot describe the anisotropic stress-strain behavior of anisotropically consolidated clay.A new model,which can be adopted for anisotropically consolidated soft clay,was developed here based on the modified Cam-Clay model.An anisotropic tensor and a shape parameter were introduced in the yield surface of the model.Initial value of the anisotropic tensor was determined by the initial consolidation stress state,and its evolution was described by a rotational hardening law both depending on plastic volumetric and deviatoric strain.The shape parameter enhanced the flexibility of the yield surface.Effectiveness of the model was verified by the triaxial experimental data of kaolin clay,boston Blue clay and Otaniemi clay.

Microphysics of rocksalt flow in nature

Abstract: To model the flow of rocksalt in nature, data on the steady-state rheological behaviour of salt are needed. This paper examines the state of the art in this field. Experimental results show that at 20-200°C and strain rates below - 10 -7 s -1 flow is controlled by dislocation cross-slip and/or climb. Depending on brine content, pressure solution creep and recrystallization can also occur. Combining the various laboratory flow laws leads to a deformation map which predicts that flow under natural conditions should be dominated by climb-controlled dislocation creep, and/or pressure solution. This picture is confirmed by microstructural analysis of natural salts, justifying the application of laboratory flow laws to model salt tectonic processes.

State-of-art of research on mechanical properties of frozen soils

Abstract: China has a large area with seasonally and perennially frozen soils.It is necessary to study mechanical properties of frozen soils for the sake of constructions in cold regions,so as to guarantee their stability.In this paper,the distribution of frozen soils in China and the main features of frozen soils differing from unfrozen soils,are briefly described firstly.Generally speaking,frozen soil mechanics consists of two main aspects,i.e.freeze-thaw related problems and mechanical properties of the already-frozen soils.Frost heave,thaw settlement and freeze-thaw induced changes in mechanical properties are freeze-thaw related problems.Frost heave has been extensively studied.Various theories have been put forward to describe the mechanism of ice segregation which is considered as the main cause of frost heave;and some theories have even been applied to quantitative analysis.The study of thaw settlement has a long history,while most of the previous studies still stay in empirical stage.Thaw consolidation has been studied;but it has considerable limitations so far.Therefore,we suggest that the artificial neural network could be used to improve the precision and applicability in estimating thaw settlement on the one side,large strain theory could be used to improve thaw consolidation theory.For the already-frozen soils,this paper summarizes the previous studies on strength,stress-strain relationship and dynamic properties.Study of the strength of frozen soil borrows strength theories for unfrozen soils;however,they can hardly reflect stress melting of frozen soils under high stresses.The previous studies of stress-strain relationship of frozen soils have been focusing on creep;and the empirical relationship directly obtained from testing data is the mainstream.Influence of temperature on dynamic parameters of frozen soils seems to be the only task in frozen soil dynamics for a long time;while influence of frozen layer in dynamic response of a site has attracted attentions in recent years.At last,physico-mechanical processes involved in deformation of constructions in permafrost regions are briefly analyzed.