SYMPOSIA PAPER Published: 01 January 1970

Methods for Determining Deformation Modulus Used by the Bureau of Reclamation


More complex foundations are being considered for concrete dams today than in past years. Large-scale in situ jacking tests capable of obtaining more data on rock behavior and jacking equipment which can apply total loads of 900,000 lb (408,240 kg) to 32,000,000 lb (14,515,000 kg) and measure up to 66 sets of rock deformations have been developed. Total rock surface areas under a maximum load of 1000 psi (70 kg/cm2 varied from 6.25 ft2 (0.58 m2) to 225 ft2 (21 m2). Hydraulic rams and large flatjacks were used to apply the load to rock. The large-scale jacking tests bring fractures and joints into play and measure their effects at depth by precisely monitoring the numerous anchor displacements in NX boreholes.

Author Information

Wallace, GB
U. S. Bureau of Reclamation, Denver, Colo.
Slebir, EJ
U. S. Bureau of Reclamation, Denver, Colo.
Anderson, FA
U. S. Bureau of Reclamation, Denver, Colo.
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Developed by Committee: D18
Pages: 3–26
DOI: 10.1520/STP29137S
ISBN-EB: 978-0-8031-4590-0
ISBN-13: 978-0-8031-0047-3