Mathematical Problems in Engineering / 2019 / Article / Tab 5

Research Article

Evaluation of Ground Surface Pregrouting in a Mountain Tunnel Based on FAHP

Table 5

Five curve types of the water pressure test.

Curve typesRelationships between pressure and flowCharacteristics of curve typesDepictions

Type ATwo curves (1-2-3 and 3-4-5) are straight lines originating at (0, 0) and are coincidentAn excellent condition, where the seepage form is laminar flow. Fissures do not change throughout the test.

Type BTwo curves (1-2-3 and 3-4-5) converge to the Q-axis and coincideAn acceptable condition, where the seepage form is turbulent flow. Fissures do not change throughout the test.

Type CTwo curves converge (1-2-3 and 3-4-5) to the p-axis and coincideAn acceptable condition where the fissure form changes and the permeability of the rock mass increases as the test pressure increases, but the change is temporary and reversible. As the pressure decreases, the fissures return to the original form, showing a behavior of elastic expansion.

Type DCurve 1-2-3 converges to the p-axis and does not coincide with curve 3-4-5A bad condition, where the fissure form changes and the permeability of rock increases as the pressure increases. This change is permanent and irreversible. The flow is significantly increased and cannot be restored to its original form, indicating fissures are split.

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