**5. Comparison of results obtained from both methods**

The hydraulic fracturing tests were conducted by using high flow rate technique in fractured rock mass and normal flow rate technique in good rock mass zones in the same boreholes. A total of 24 hydraulic fracturing tests were attempted in different EX size boreholes inside the tunnels of proposed powerhouse and Intake drift areas. The testing zones selected at the depths between 7 and 27 m. In most hydraulic fracturing testing, at the depth of 7–30 m, pumping rates of 4–6 l/min are sufficient to conduct the entire test. Such pumping rates were sufficient to conduct good hydraulic fracturing tests, but proved to be insufficient for tests in the fractured zones. As this problem became apparent during testing, a high-pressure pump was used in order to achieve higher pumping rates (up to 18 l/min). HTPF method was used for data interpretation and the analysis of the results was done by using PLANE software and GENSIM.

The software PLANE incorporates the impression data with the compass data as input parameters and gives the strike, dip and dip direction as the output known as fracture orientation data.

The software GENSIM computes the stress field based on measured shut in pressure and fracture orientation data. Assumption is that the vertical stress is a principal stress and is equal to the weight of the overburden. The powerful GENSIM program requires only the shut-in pressure and the orientation of an induced or preexisting fracture. As a result, the role of breakdown pressure and fracture reopening pressure are nil as far as stress computation is concerned [17].

After obtaining the results by both methods it is observed that the direction of maximum principal horizontal stress is not changed. The magnitude of maximum and minimum principal horizontal stresses is also almost same with negligible or fraction of difference. The stress gradients are observed in fractured and nonfractured rock mass. No influence found of any induced stress at any location. The results are compared in **Table 9**.


**Table 9.**

*Comparison of results determined in fractured and non-fractured rock mass.*
