| 摘要 |
FIELD: borehole drilling technology. SUBSTANCE: grouting mortar is delivered to space beyond tube string, excess pressure is transferred from mouth to this space to compensate for reduced hydrostatic pressure of grounding mortar, and removal of excess pressure. Initially excess pressure is created by value equal to loss of pressure for hydraulic resistance in space beyond string at end of grouting process and it is maintained up to moment of thickening of grouting mortar at bottom, then it is gradually increased up to moment of thickening of grouting mortar at borehole mouth. Value of excess pressure is determined by formula: Pex=Ps+Phw-Pl<Phb, where Ps - pressure losses for hydraulic resistance in space beyond string at end of grouting, MPa; Phw - pressure of hydrostatic column of washing liquid, MPa; Pl - pressure of hydrostatic column of solution liquid, MPa; Phb - pressure of hydraulic stratum breakage or absorption, MPa. EFFECT: high efficiency. |
