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Determination of the bounding backfill loads for lateral deflection analysis of a downhole canister

Technical Report ·
OSTI ID:6942705
The main objective of this study is to develop analytical models that will allow us to predict the effect of the hole geometry, stemming material, canister position, and the canister rigidity on the distortion of the canister structure. Numerous potential sources of loads that cause canister distortion are identified. Three loading scenarios that can potentially produce uneven loads during stemming are identified: an off-center canister, a canted canister, and the canister in an imperfect hole. The canister structure is modeled by an equivalent continuum methodology. A simple procedure is proposed for analysis of backfill-canister interaction. Two steps are most important for the proposed procedure: determination of unbalanced bounding backfill loads and estimation of the lateral resistance of the stemming material. Theories for determination of unbalanced bounding loads on the canister are developed based on extending the classical Janssen's arching theory, which applies only to simple silo loads in the symmetrical case, to the problem of the loading in an eccentric or a nonvertical annular emplacement system. A computer program has been developed for the general procedure of unbalanced bounding loads calculation. The lateral force-deflection characteristics on the buried canister are developed on the basis of laboratory experimental data. Unbalanced pressures and loads are calculated on the Bodie canister for three postulated loading scenarios. The order of magnitude of calculated pressures and loads is reasonable in comparison to the measured data. The variation of lateral loads with depth is significant for nonvertical and washout cases. The effect of the loading scenarios on the magnitude and the profile of calculated lateral loads is important. 41 refs., 22 figs., 4 tabs.
Research Organization:
Lawrence Livermore National Lab., CA (USA)
DOE Contract Number:
W-7405-ENG-48
OSTI ID:
6942705
Report Number(s):
UCID-21523; ON: DE89003714
Country of Publication:
United States
Language:
English