Pretest reference calculation for the 6.1 meter (20 ft) wide drifts of the Geomechanical Evaluation (WIPP Room G in situ experiment)

A pretest reference calculation for the Geomechanical Evaluation or Room G experiment is presented. The Geomechanical Evaluation is one of several large-scale in situ tests currently under construction near Carlsbad, New Mexico, at the site of the Waste Isolation Pilot Plant (WIPP). The Room G experiment consists of isolated, two-dimensional drifts with different room spans, an isolated drift intersection, and a wedge pillar. The primary purpose of the experiment is to provide data for validating computational modeling capabilities used in analyzing nuclear waste repositories in salt. The calculation presented here addresses only one portion of the test, namely isolated drift configurations which are initially 6.1 m (20 ft) wide by 3.05 m (10 ft) high. The Geomechanical Evaluation is heavily instrumented for monitoring deformations due to creep of the salt. Data from the experiment are not available at the present time, but the measurements for Room G will eventually be compared to the results presented in this report to assess and improve structural modeling capabilities for the WIPP. The model used for this calculation represents the state of the art at the present time. A large number of plots are included since an appropriate result is presented for every gage location associated with the 6.1 m wide drifts. 53 refs., 53 figs., 3 tabs