| 摘要 |
<p>The invention relates to a method of laying an underground elongate member such as a cable or pipe. The member is installed underground by directional drilling including being drawn through an unlined bore of larger cross section with lubricant mud being supplied to the space between the member and the bore. The lubricant mud is replaced by a product typically comprising bentonite and a setting agent such as cement. In time, the cement transforms the product into a solidified jacket around the elongate member. Preferably the product contains a pigment. The invention also relates to a two-stage apparatus for enlarging the hole and drawing the cable or pipe into the hole. The invention further relates to a material mix for use as the product.</p> |
