DOE 2000. - Waste Isolation Pilot Plant - U.S. Department of Energy

WIPP RH PSAR DOE/WIPP-03-3174 CHAPTER 4
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Data Collection and Analysis: Field activities are established for data collection from geotechnical
instrumentation, fracture and excavation effect surveys, and general observations. Ground conditions
are examined on a regular basis (at the beginning of each shift, weekly, monthly, and annually
according to regulatory requirements and operating plans). Monitoring results are analyzed in
comparison with established design criteria, and are utilized in a variety of computer models. The
results of these studies are published in a variety of formats ranging from specific reports through
frequent regular assessments (e.g., bi-monthly summaries) to comprehensive annual reports (e.g.
Geotechnical Analysis Report), which are available to the public in reading rooms. All data and
related documentation are maintained in databases which are regularly subjected to quality assurance
audits. These data are available to those who make independent assessments.
The fundamentals on which the ground control program at the WIPP facility are based are as follows:
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Ground stability is maintained as long as access is possible.
Ground control maintenance efforts increase with the age of the openings.
Ground control plans are specific but flexible.
Regular ground control maintenance is required.
The ground control program at the WIPP facility uses observational experience and analysis of salt
behavior underground to enable various projections regarding future ground support requirements. This
approach recognizes that salt moves or creeps. Because of its plastic nature, salt will flow into an
excavated opening. To provide long-term ground support, the ground control system must:
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Accommodate the continuous creep of salt
Retain broken fractured rock in the back or rib
Two major categories for support systems are rock bolts and supplementary systems. The rock bolt
systems are mechanically-anchored bolts and resin-anchored threaded rods. The supplementary systems
include cables with mesh, trusses, and the Room 1, Panel 1 design.
Initial Roof Support System (Rock-Bolt System)
Prior to waste emplacement in any specific area (room), the plans (for Panels 2-8) are to spot bolt with
short, mechanically anchored bolts only as necessary, if spalls or loose ground are encountered during
and after the mining process. Mesh may be used in conjunction with these bolts to secure any loose
ground encountered during normal inspection processes. These bolts would not penetrate through to the
next clay/anhydrite interface, and would be anchored within the beam formed by the mine roof and the
clay/anhydrite interface above. This is the primary or initial support which will be used in Panels 2-8.
4.3-12 January 28, 2003