PUNCTURES

The punctures controlled in plan and profile are made according to the dry method (without the use of liquid fillers – bentonite, etc.) without removal of the soil from the working channel.

Categories of the soil:  all types of soils, except for rocks.

Works for making the punctures may be performed from a pit to a pit (MNB-30, MNB-50, MNB-125), if necessary, due to especially constrained conditions, from a well or formworks OR-1.5 to a well (MNB-50).

TECHNOLOGICAL SEQUENCE OF PUNCTURE ARRANGEMENT

	1. Pilot well Preliminary works: Construction of working and receiving pits, installation of MNB equipment to the working pit along with connection of hydraulic hoses to the hydraulic plant. Pressure is developed in the power unit (hydraulic plant) which is transferred to the puncture unit (the working cylinder) by the system of hoses. A rod is pressed inside. Then another rod is screwed on and pressed into the soil. Simultaneously with pressing the rods an operator controls direction of the drill travel with the aid of a locator.
	If the drill deviates in excess of the allowed values the direction is leveled out by achieving the required horizontal and vertical position of the drill tip in the soil. Note: direction of the drill travel is achieved owing to a special design of its tip and alternation of reciprocal and rotational motion.
	The boring process along with the constant location control of the precise location of the drill tip in the soil is continued up to drill getting to the receiving pit in accordance with the designed data.
	2. Boring with expansion After drill getting to the receiving pit it is dismantled and mounted to the first rod of the expander. Then the second rod is connected. The expander is pulled inside to the whole length of the second rod. The pulled rod is taken off in the working pit. Then the process of pulling inside is repeated. In the receiving pit the rods are expanded and in the working pit they are removed. After expander getting to the working pit the expander is replaced for another one having a bigger diameter. The process pulling inside along with expander replacement for a bigger diameter is continued until the boring diameter exceeds the pulled pipe diameter. Note: expansion of the channel is carried out without pressing the soil out (due to soil compaction).
	3. Pulling the polyethylene pipe into the well A clamp is installed onto a preliminarily welded (by means of contact butt welding) polyethylene pipe and is connected with the expander of the rods. The polyethylene pipe is pulled into the well until it appears in the working pit.