A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Summary The modified borehole jacking method, as introduced by De La Cruz in 1978, has important theoretical advantages over the common method which is associated with the name Goodman. So far, however, the modified method has not succeeded, mainly due to a lack of suitable instrumentation. To overcome this problem, a new type of modified borehole jack has been designed, built and tested. The new jack incorporates two highly innovative components: a recoverable sensor for measuring tangential strain at borehole surfaces and stacked hydraulic cylinders for extra-high load outputs. The new jack has been developed to the point at which its technical feasibility under field conditions, including its capability of yielding meaningful results, is demonstrated. Calibration in a hollow steel cylinder revealed that the new modified jack yields the correct Young's modulus within an error margin of less than ±5%. In-situ jacking tests were carried out at a major dam construction site. Results were obtained from both common and modified borehole jacking and from conventional laboratory testing of drill cores. The results of these tests are presented and discussed against the background of the particular rock conditions at the site.
Summary The modified borehole jacking method, as introduced by De La Cruz in 1978, has important theoretical advantages over the common method which is associated with the name Goodman. So far, however, the modified method has not succeeded, mainly due to a lack of suitable instrumentation. To overcome this problem, a new type of modified borehole jack has been designed, built and tested. The new jack incorporates two highly innovative components: a recoverable sensor for measuring tangential strain at borehole surfaces and stacked hydraulic cylinders for extra-high load outputs. The new jack has been developed to the point at which its technical feasibility under field conditions, including its capability of yielding meaningful results, is demonstrated. Calibration in a hollow steel cylinder revealed that the new modified jack yields the correct Young's modulus within an error margin of less than ±5%. In-situ jacking tests were carried out at a major dam construction site. Results were obtained from both common and modified borehole jacking and from conventional laboratory testing of drill cores. The results of these tests are presented and discussed against the background of the particular rock conditions at the site.
A new modified borehole jack for stiff rock
1987
Article (Journal)
English
Local classification TIB:
560/4815/6545
BKL:
38.58
Geomechanik
/
56.20
Ingenieurgeologie, Bodenmechanik
A new modified borehole jack for stiff rock
| Springer Verlag | 1987
Measurement of viscoelastic property of rock by borehole jack test
| British Library Conference Proceedings | 1981
A modified NX-borehole jack with flexible loading platens
| British Library Online Contents | 2016
A modified NX-borehole jack with flexible loading platens
| British Library Online Contents | 2016
A modified NX-borehole jack with flexible loading platens
| Online Contents | 2016