Earth penetration

A ground penetrating device for forming a borehole, from a ground surface, having radial and lateral dimensions and continuously penetrating the ground by elongation of the borehole, said device comprising

• (a) a tip portion for penetrating the ground to form the borehole,
• (b) a plurality of means for applying lateral thrust to said tip portion for providing a penetrating force thereto, each of said lateral thrust applying means comprising
• (i) a generally tubular mandrel of a fixed length,
• (ii) a pair of generally toroidal lateral force cells mounted on said mandrel and each being expandable and retractable in said lateral direction, the combined length in the lateral direction of said lateral force cells being a fixed amount less than the length of said mandrel, and each of said lateral force cells having a substantially fixed radial dimension, the radial expansion thereof being restricted to said radial dimension,
• (iii) a pair of generally toroidal radial force cells mounted on said mandrel and having a substantially fixed lateral dimension but being expandable in the radial direction from a first position wherein the walls of the borehole are not engaged thereby, to a second position wherein the walls of the borehole are securely engaged thereby and said cell is effectively anchored to the borehole walls at the area of engagement with said walls,
• (iv) said radial and lateral force cells being alternately disposed along said mandrel and adjacent one of said plurality of means for applying lateral thrust having alternate lateral and radial cells, and
• (v) means for slectively applying fluid under pressure to said force cells to provide alternate expansion and contraction thereof for movement of said entire lateral thrust applying means in the lateral direction for applying a lateral thrust,
• (c) means for connecting said plurality of lateral thrust applying means together so that the lateral thrust supplied thereby is cumulative, and
• (d) means leading from said thrust applying means to the surface of ground penetrated by said device.

A ground penetrating device for forming a borehole, from a ground surface, having radial and lateral dimensions and continuously penetrating the ground by elongation of the borehole, said device comprising

• (a) a tip portion for penetrating the ground to form the borehole,
• (b) a plurality of means for applying lateral thrust to said tip portion for providing a penetrating force thereto, each of said lateral thrust applying means comprising
• (i) a generally tubular mandrel of a fixed length,
• (ii) a pair of generally toroidal lateral force cells mounted on said mandrel and each being expandable and retractable in said lateral direction, the combined length in the lateral direction of said lateral force cells being a fixed amount less than the length of said mandrel, and each of said lateral force cells having a substantially fixed radial dimension,
• (iii) a pair of generally toroidal radial force cells mounted on said mandrel and having a substantially fixed lateral dimension but being expandable in the radial direction from a first position wherein the walls of the borehole are not engaged thereby, to a second position wherein the walls of the borehole are securely engaged thereby and said cell is effectively anchored to the borehole walls at the area of engagement with said walls,
• (iv) said radial and lateral force cells being alternately disposed along said mandrel and adjacent ones of said plurality of means for applying lateral thrust having alternate lateral and radial cells, and
• (v) means for selectively applying fluid under pressure to said force cells to provide alternate expansion and contraction thereof for movement of said entire lateral thrust applying means in the lateral direction for applying a lateral thrust,
• (c) means for connecting said plurality of lateral thrust applying means together to provide for steering of said device by allowing either parallel or degrees of non-parallel disposition between said mechanisms, and
• (d) means leading from said thrust applying means to the surface of ground penetrated by said device.

A soft ground penetrator comprising

• (a) a sharpened tip means capable of penetrating soft earth when a lateral thrust is supplied thereto for forming a bore of a given diameter,
• (b) means for supplying lateral thrust to said sharpened tip means,
• (c) earth compacting means associated with said tip means for expanding the size of a bore formed by said tip means by compacting earth adjacent the bore formed by said tip means, said tip means being movable with respect to said earth compacting means, said earth compacting means comprising a generally conically shaped rigid member, a plurality of individual inflatable cells disposed about said rigid member and extending in increasing diameter from said tip means toward said means for supplying lateral thrust to said compacting means, each of said cells having an inflated diameter substantially the same as or larger than the deflated diameter of the next larger cell, and means for selectively applying fluid under pressure to said inflatable cells, and
• d) means for supplying lateral thrust to said earth compacting means to provide for lateral movement thereof.

A force applying device comprising

• (a) a cylinder,
• (b) a piston disposed in said cylinder, said piston being spaced from said cylinder a given distance .alpha. around the whole periphery of said piston,
• (c) a bag-like flexible membrane being disposed in said cylinder engaging said piston, said flexible membrane having an uninflated diameter less than or equal to the diameter of said piston, and having a thickness .beta., wherein 2.beta. is less than .alpha., and
• (d) means for supplying fluid under pressure to said flexible membrane to place said membrane in tension so that it always engages the interior walls of said cylinder and so that it has a convolution in the area between said piston periphery and the cylinder interior walls, a double thickness of said membrane being disposed in said area, and said fluid supplying means being capable of supplying enough fluid under pressure to cause relative movement of said piston with respect to said cylinder.

A method of soft earth penetration utilizing a penetrating device having a sharpened tip portion and a conical compacting portion including a plurality of inflatable radially expandable cells mounted on a rigid conical member of said compacting portion, said cells being arranged in increasing diameter from said tip means away therefrom, said method comprising the steps of

• (a) making a relatively small diameter bore in the earth by supplying a lateral thrust to said penetrating tip to move said tip relative to said compacting means,
• (b) supplying a lateral thrust to said compacting means, with said cells deflated, to move it into engagement with said penetrating tip while allowing said tip to be retracted,
• (c) radially expanding said cells to cause compaction of the earth thereabouts a sufficient amount so that a void is formed by each cell of great enough diameter so that the next largest cell may be laterally moved thereinto in its deflated position,
• (d) deflating all said cells after earth compaction thereby, and
• (e) repeating steps (a)-(d) until a bore of sufficient length is created.

A method of supplying a lateral thrust to a tubular mandrel to move it forward, the mandrel being of fixed lateral dimension and having disposed thereon two torodial laterally expandable force cells with constant radial dimension, and two toroidal radially expandable force cells with constant lateral dimension, said radial and lateral cells alternating and a lead lateral cell and lead radial cell being provided, said method comprising the steps of sequentially

• (a) expanding the rear radial cell and the lead lateral cell,
• (b) expanding the lead radial cell,
• (c) contracting the rear radial cell,
• (d) expanding the rear lateral cell and contracting the lead lateral cell,
• (e) expanding the rear radial cell,
• (f) contracting the lead radial cell, and
• (g) expanding the lead radial cell while contracting the rear lateral cell.

An assembly for providing lateral thrusts in an area having a confined radial dimension, said assembly comprising

• (a) a generally cylindrical mandrel of a fixed lateral length,
• (b) a pair of lateral force cells mounted on said mandrel and each being expandable and retractable in said lateral direction, the combined length in the lateral direction of said lateral force cells being a fixed amount less than the length of said mandrel, each of said lateral force cells having a substantially constant radial dimension,
• (c) a pair of radial force cells mounted on said mandrel each having a substantially fixed lateral dimension but being expandable in the radial direction,
• (d) said radial and lateral force cells being alternately disposed on said mandrel,
• (e) means for selectively expanding or contracting said force cells for movement of said assembly in the lateral direction, and
• (f) constant volume fluid supplying means for supplying a constant volume of fluid to each of said radial force cells upon actuation by said means for supplying fluid under pressure, said means for supplying a constant volume of fluid to each of said radial force cells including a piston movable in a cylinder, and a flexible membrane disposed around said piston and engaging the interior walls of said cylinder, said cylinder being disposed adjacent one of a pair of side plates defining the lateral extent of said radial cell and an aperture being defined in said side plate, and said piston having a sealing means formed thereon so that in the expanded position of said flexible member said piston sealing means closes off said aperture and prevents further delivery of fluid from said cylinder to said radial force cell.

A ground penetrating device for forming a borehole, from a ground surface, having radial and lateral dimensions and continuously penetrating the ground by elongation of the borehole, said device comprising

• (a) a tip portion for penetrating the ground to form the borehole,
• (b) means for applying lateral thrust to said tip portion for providing a penetrating force thereto, said lateral thrust applying means comprising
• (i) a generally tubular mandrel of a fixed length,
• (ii) a pair of generally toroidal lateral force cells mounted on said mandrel and each being expandable and retractable in said lateral direction, the combined length in the lateral direction of said lateral force cells being a fixed amount less than the length of said mandrel, and each of said lateral force cells having a substantially fixed radial dimension,
• (iii) a pair of generally torodial radial force cells mounted on said mandrel and having a substantially fixed lateral dimension but being expandable in the radial direction from a first position wherein the walls of the borehole are not engaged thereby, to a second position wherein the walls of the borehole are securely engaged thereby and said cell is effectively anchored to the borehole walls at the area of engagement with said walls,
• (iv) said radial and lateral force cells being alternately disposed along said mandrel, and
• (v) means for selectively applying fluid under pressure to said force cells to provide alternate expansion and contraction thereof for movement of said entire lateral thrust applying means in the lateral direction for applying a lateral thrust,
• (c) means leading from said thrust applying means to the surface of ground penetrated by said device, and
• (d) a lateral thrust applying means power package and control means disposed on the side of said thrust applying means opposite said tip portion, said power package comprising means for utilizing the flow of drilling fluid through said drill string for powering said thrust applying means.