Multipoint grouting method and apparatus therefor

Abstract

A multipoint grouting method for effecting multipoint-injection of a ground improving material into ground to be improved such as weak ground, soft ground, flimsy ground, loose ground or the like, and an apparatus therefor are disclosed. In particular, the multipoint grouting method and the apparatus therefor are not only capable of, with respect to ground having soil layers different from each other in soil condition such as soil texture, concurrently or selectively applying optimum injection to each of the soil layers but also capable of one-, two- or three-dimensionally injecting a ground improving material into ground, and are further capable of flexibly controlling injection from a plurality of injection pipes and capable of carrying out injection concurrently or selectively from the plurality of the injection pipes to thereby increase reliability of permeation grouting into a very fine-grained soil layer and to thereby enable a shortened execution period to be realized by rapid execution. The multipoint grouting method comprises: inserting a plurality of injection pipes each having an outlet in a plurality of injection points in ground; and concurrently or selectively injecting a ground improving material, via the injection pipes, from the plurality of the outlets into the plurality of injection points; and wherein a multiple injection means is used which includes a plurality of unit pumps driven by driving means independent of each other and controlled by a centralized control means, and the plurality of the unit pumps are connected through ducts to the plurality of the injection pipes, and by operations of the plurality of the unit pumps, the ground improving material is injected from the plurality of the outlets into the plurality of the injection points in the ground. The multipoint grouting apparatus comprises: a reservoir for a ground improving material; a multiple injection means including a plurality of unit pumps and connected to the reservoir, each of the unit pumps being driven by an independent driving means and controlled by a centralized control means; a plurality of injection pipes inserted in a plurality of injection points in ground and connected to the respective unit pumps through ducts, the injection pipes each having an outlet; a plurality of rotational speed changing means which are provided for the independently driven respective unit pumps and which are controlled by the centralized control means; and a plurality of flow rate and pressure sensors provided in mid-courses of the respective ducts; and wherein the flow rate and pressure sensors transmit data signals on flow rates and/or pressures to the centralized control means to deliver under pressure the ground improving material in the reservoir to each of the injection pipes by the operation of each of the unit pumps at a desired injection rate, under desired injection pressure and/or in a desired amount of injection, thereby injecting the ground improving material concurrently or selectively from the plurality of the outlets into a plurality of injection points in the ground.

Dependencies are inferred from the claim text.