Buy article PDF
The purchased file will be sent to you
via email after the payment is completed.
US$ 35
|
Computers and Concrete Volume 19, Number 2, February 2017 , pages 171-177 DOI: https://doi.org/10.12989/cac.2017.19.2.171 |
|
|
|
Estimating of water pressure to avoid hydraulic fracturing in water pressure test |
||
Hassan Bakhshandeh Amnieh and Majid Masoudi
|
||
| Abstract | ||
| Water pressure test operation is used before the grouting to determine the rate of penetrability, the necessity and estimations related to grouting, by the penetration of water into the borehole. One of the parameters which have the highest effect is pressure of water penetration since the application of excessive pressure causes the hydraulic fracture to occur in the rock mass, and on the other hand, it must not be so small that prevents from seeing mechanical weaknesses and the rate of permeability. Mathematical modeling is used for the first time in this study to determine the optimum pressure. Thus, the joints that exist in the rock mass are simulated using cylindrical shell model. The joint surroundings are also modeled through Pasternak environment. To obtain equations governing the joints and the surroundings, energy method is used accompanied by Hamilton principle and an analytical solution method is used to obtain the maximum pressure. In order to validate the modeling, the pressure values obtained by the model were used in the sites of Seymareh and Aghbolagh dams and the relative error rates were measured considering the differences between calculated and actual pressures. Modeling in the sections of Seymareh dam showed 4.75, 3.93, 4.8 percent error rates and in the sections of Aghbolagh dam it rendered the values of 22.43, 5.22, 2.6 percent. The results indicate that this modeling can be used to estimate the amount of pressure for hydraulic fracture in water pressure test, to predict it and to prevent it. | ||
| Key Words | ||
| water pressure test; hydraulic fracture; mathematical modeling; cylindrical shell model | ||
| Address | ||
| Hassan Bakhshandeh Amnieh: School of Mining, College of Engineering, University of Tehran, Iran Majid Masoudi: Department of Mining Engineering, Faculty of Engineering, University of Kashan, Iran | ||