Hydraulic Fracturing of Soils; A Literature Review.
Abstract
New and more detailed analyses are being developed in soil mechanics for earth structure and foundation designs which require a detailed definition of in situ stresses and strains in soils. Although no tests exist that give absolute answers, numerous tests can be used as tools to determine ranges, best case, or worst case. The study reported herein is an overview of one such test or technique, hydraulic fracturing, which is defined as the formation of cracks, in soil by the application of hydraulic pressure greater than the minor principal stress at that point. Hydraulic fracturing, as a technique, has been used for many years by oil companies but up intil the last 10 to 15 years this method has not been used extensively to determine stresses in a soil medium. Numerous tests have been conducted in the laboratory and in the field to validate mathematical theories of soil stress with actual data. Laboratory tests have been successful in determining stresses for a controlled test and a controlled sample, but field tests have yet to attain more than fair accuracy under uncontrolled soil conditions. There is evidence presented in a recent (June 1975) ASCE In Situ Measurement Conference that there is disagreement of values obtained by different methods (conventional laboratory, pressuremeter, vane shear, etc.) of determining minor stresses and it is suggested that fracturing is just another tool that helps to define a range of values. While there are reservations concerning hydraulic fracturing as a means for determination of lateral stresses, the technique can still be used for determining in situ total stress and permeability at a point in a cohesive soil.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1977
- Accession Number
- ADA038443
Entities
People
- Roy E. Leach