Pressures and displacements around a lined shaft in weak rock

132A At Killingholme, Humberside, UK, construction is underway on a total of 3km of tunnels driven from the bottom of two sets of 200m deep, 2m diameter shafts. The shafts are required to excavate two approximately 150,000cu m caverns in Upper Cretaceous Chalk, forming the first purpose built Liquid Petroleum Gas storage facility in the UK. Construction problems have been aggravated by a shaft flooding and the need to introduce drill and blast tunnelling to achieve production in the resistant chalk geology. 844086 Ultimate strength of concrete shaft linings and its influence on design Auld, F A In: Strata Mechanics (paper to the Symposium on Strata

Mechanics, Newcastle upon Tyne, 5-7 April 1982) P134-140. Publ Amsterdam." Elsevier, 1982 The paper sets out formulae for determining the elastic, pure plastic and Coulomb plastic stresses in. a thick cylinder subjected to external pressure. It is then shown how the three types of stress derivation can each be applied in the design of concrete shaft linings. Consideration is given to both the long term permanent loading and the short term, backwall grouting situation. 844O87 Measurement of stresses, strain and temperature in concrete in shafts and imets Altounyan, P F R In: Strata Mec&mics (paper to the Symposimn on Strata

MecAaMcs, Newcastle upon Tyne, 5-7 April 1982) P154-159. Publ Amsterdam: Elsevier, 1982 An instrumentation system has been developed to measure stress, strain and temperatures in concrete shaft and inset linings, using vibrating wire gauges. 844088 Pressures and displacements around a lined shaft in weak rock Gilbert, M J In: Strata Mecimaics (paper to the Symposimn on Strata

Meelamics, Newcastle upon Tyne, 5-7 April 1982) P174-177. Publ Amsterdam: Elsevier, 1982

844O90 Near-surface underground constructions in mixed abruptly changing ground Valore, C

Proc 5th Congress of the International Society for Rock Mechanics, Melbourne, 10-15 April 1983 V1. PC287-C294. Publ Rotterdam: A. A. Balkema. 1983 The subsoil of Palermo is composed of rocks and soils of widely different physico-mechanical properties which form structurally complex formations. Design criteria based on an observational approach, for near-surface underground structures built by tunnelling or trenching in mixed, abruptly changing ground, are suggested. Water circulation is controlled by complicated boundary hydraulic conditions. The ground geotechnical properties and effectiveness of the recommended approach are discussed with reference to a long sewer trunk, 5m wide, presently under construction. 844091 Analysis of creep and relaxation around an underground opening in rock salt (In German) Borm, G

Proc 5th Congress of the lnternatiomal Society for Rock Mechanics, Melbourne, 10-15 April 1983 V2, PD23-D27. Publ Rotterdam: A. A. Balkema, 1983 The rheological behaviour of rock salt around underground cavities is studied by analytical and numerical calculations. As a material model a nonlinear generalized Maxwell body is assumed, where the rate of the viscous deformation is a power function of the effective stress. Special emphasis is directed to the interaction of creep and relaxation in the ground. Stress relaxation is calculated for nonlinear viscoelastic rock materials. The time dependent maximum circumferential stresses form a temporary screen around the opening, similar to the nonmonotonous distribution of maximum tangential stresses in elastoplastic tunnel analyses. The flow condition depends on the rate of deformation. As a result of stress relaxation, the rates of cavity wall convergences decrease monotonously with time, indicating apparently strain hardening material properties. The convergences of the cavity walls can be predicted by trend analysis, if the material deforms continuously, and if the boundary conditions are independent of time. Auth.

Models of lined shafts in soft rocks are commonly based on the twin assumptions of an elastic lining and an isotropic stress distribution. These assumptions are tested against data from an instrumented shaft. It is shown that shaft behaviour is significantly different from these model predictions. In particular, concrete shrinkage, shaft-lining bonding and stress anisotropy are shown to be of crucial importance.

844O92 Containment of unlined caverns used for LPG storage (In French) Berest, P; Morisseau, J M; Noe, J M; Souquet, G

844089 Creep closure of caverns in rocksalt Passaris, E K S; Horseman, S T In: Strata Meckuic$ (paper to the S . V W

The containment of unlined caverns used for compressed gas storage and located in water bearing formations is considered. The difference in pressure between the surrounding aquifer and the stored products required to ensure the containment is analysed; the hydraulic gradient method is examined and two new ideas, the threshold pressure of the gas and the form factor, are introduced.

oR Strata Meclumics, Newcastle upon Tyne, 5-7 April 1982) P178-I83. Publ Amsterdam: Elsevier, 1982 Analytical solutions for the prediction of closure rates of internally pressurized storage caverns in rock salt are developed for cylindrical and spherical caverns. Since the stresses around the caverns are statically indeterminate the derived solutions are only applicable to problems examined some time after cavern construction.

Proc 5th Congress of the International Society for Rock Mec&mics, Melbourne, 10-15 April 1983 V2, PD221-D225. Publ Rotterdam: A. A. Balkema, 1983

844093 Mechanical b~lmviour of deep salt caverns for the storage o f hydroc~bous (In French) Berest, P; Nguyen Minh, D

Proc 5tk Cong~ss of the IMer~Jiou~ Society for Rock Mec&mics, Melbourne, 10-15 April 1983 V2, PD227-D231. Publ Rotterdam: A. A. Balkema, 1983 Due to delayed effects in the rheological behaviour of rock salt, the interpretation of lab test results has led to errors in calculations for underground caverns. It is shown that on the basis of available in situ data a viscoplastic model can be used to predict