Stress analysis

See also: 902087, 902439

902242 Deformation analysis of sands in cubical and hollow cylinder devices Chang, C S; Misra, A; Weeraratne, S J lnt J Num Anal Meth Geomech VI3, N5, Sept-Oct 1989, P493-510

Granular soil materials are considered to deform due to rela- tive movements of clusters of particles. Using this deformation mechanism, the kinematics of soils are developed, and a strain tensor in terms of local displacements and geometric measures is introduced. Using the local constitutive law, relations between stress and strain of the medium are developed. Strain hardening and material anisotropy effects are included. Model predictions are compared to results of tests on sand in cubical and hollow-cylinder devices.

902243 Application of a continuum damage model in the finite element simulation of the progressive failure and localization of deformation in brittle rock structures Singh, U K; Digby, P J lnt J Solids Struct V25, N9, 1989, P1023-1038

A previously developed continuum damage model for brittle rock under plane strain conditions is extended to simulate pro- gressive failure and formation of Iocalisation bands in brittle rock structures under both tensile and compressive loading. It is implemented in a finite element program to describe tensile testing, shear band formation under brittle loading, and fail- ure around a tunnel.

902244 Construction for shear stress on a generally-oriented plane. Short note Means, W D J Struct Geol Vll, N5, 1989, P625-627

A method is presented to find the magnitudes and directions of shear and normal stresses and the sense of the shear stress on a generally oriented plane in 3 dimensions when the princi- pal stresses are known. It involves graphically decomposing the 3 dimensional stress tensor into a hydrostatic component, a uniaxial tension and a uniaxial compression. It is easier to understand geometrically than the usual decomposition into a mean stress and a deviator.

902245 Elastic-plastic constitutive model for the behaviour of improved sandy soils Hirai, H; Takahashi, M; Yamada, M Soils Found V29. N2, June 1989, P69-84

A constitutive model for cement stabilised sands under mono- tonic loading is presented. It is derived from the non-associ- ated flow rule. Plastic potential is a generalisation of that in the Modified Cam Clay model. The hardening function con- siders plastic work due to change in both volume and shape. Two yield functions are used to adequately depict plastic behaviour under general stress conditions. The model gives predictions in satisfactory qualitative correspondence to results of laboratory triaxial and compression tests.

95A

902246 Analysis of non-smooth deformation of rock masses Xie Heping; Chen Zhida Proc International Symposium on Modern Mining Technology, Tnian, October 1988 P278-285. Publ Taian: Shandong Institute of Mining and Technology, 1988

Deformation of jointed rock masses is analysed using a dis- continuum mechanics approach. Constitutive laws of intact rock and rock joints are examined, and a new variational prin- ciple for analysis of intact or jointed rock masses is derived. A finite element approximation is presented. Numerical exam- ples examine discontinuous deformation caused by geological fracture structures and excavation of a jointed rock mass.

902247 Determining stresses around workings taking rock technological heterogeneity into account Fotieva, N N; Sammal, A S Proc International Symposium on Modern Mining Technology, Taian, October 1988 P286-293. Publ Taian: Shandong Institute of Mining and Technology, 1988

Analysis of stresses around underground structures is compli- cated by the reduction of rock mass deformability close to the working face due to blasting damage. An analysis technique presented for this problem is based on the plasticity theory flat contact problem for a multi-layer noncircular ring. Examples of its application are presented.

902248 Semi-analytical element method for three-dimensional elasto- plastic analysis of tunnels Zuo Guohua; Yang Yuanlin; Zheng Yingren Proc International Symposium on Modern Mining Technology, Taian, October 1988 P306-314. Publ Taian: Shandong Institute of Mining and Technology. 1988

The Semi-Analytical Element Method (SAEM) for stability analysis is presented. It reduces an essentially three dimen- sional problem to one dimension. The displacement functions of the rock are given as products of analytical solutions in the axial and radial directions and a polynomial in the angular direction. An elastoplastic analysis using the incremental itera- tion method is presented. The speed of calculation allows its use in NATM projects where rapid feedback cannot be obtained by conventional methods using generally available computing power.

902249 Special problems in the computer aided analysis of underground structures Kumar, P; Singh, B; Sharma, S P Proc Symposium on Computer Aided Design and Monitoring in Geotechnical Engineering, Bangkok, 3-6 December 1986 P727-746. Publ Bangkok: AIT, 1986

It is suggested that for the case of underground structures, sophisticated modelling of the geology and material properties followed by simplified analysis may give better results than sophisticated analysis of a simplified numerical model. Three dimensional problems can be reduced to two dimensions and analysis of the unbounded domain is possible by using quasi plane strain elements and infinite elements respectively. Deri- vation of these elements is described. Infinite elements are demonstrated for the cases of deep and shallow underground structures and parallel twin tunnels.

© 1990 Pergamon Press pie. Reproduction not permitted