Stress relaxation gage

Claim 1

A method for measuring deformation in walls of a tunnel during excavation thereof from a working face at an end of a preexisting passage leading thereto comprising: drilling a first plurality of substantially aligned holes to extend from the openings thereof spaded around in an area on said working face surrounding the periphery of the opening said excavation is to make in said working face approximately perpendicularly to said working face; drilling in areas of stable walls forming said preexisting passage, which are adjacent to said working face, a second plurality of holes having openings, respectively spaced around in correspondence with said first hole openings; constituting contiguous to the deep end of each of said first holes an anchor supporting an articular connective element, and inserting thereafter, so as to join with said anchor at said connective element, a strain data sensing probe having an end extending outside said hole whereby the longitudinal axes of said probes cross extensions of longitudinal axes of said second holes; affixing in each said second hole, substantially along said axis thereof, a beam having an end thereof extending outside said hole and disposed adjacent said outside probe extension; coupling each said adjacent beam and sensing probe ends outside their respective holes whereby each sensing probe is maintained stabilized with respect to said walls of said preexisting passage, and centered in said working face holes out of contact with the walls thereof, and reading signal outputs of said plurality of sensing probes as said excavation progresses to form a tunnel extension of said preexisting passage whereby the derivation of rock competence information on said tunnel walls is enabled and wherefrom support problems of subsequent excavations to further extend said tunnel walls can be anticipated.

Claim 2

A method for measuring deformation in walls of a tunnel during excavation thereof from a working face at an end of a preexisting passage leading thereto comprising: drilling a first plurality of substantially aligned holes to extend from the openings thereof spaded around in an area on said working face surrounding the periphery of the opening said excavation is to make in said working face approximately perpendicularly to said working face; drilling in areas of stable walls forming said preexisting passage, which are adjacent to said working face, a second plurality of holes having openings, respectively spaced around in correspondence with said first hole openings; constituting contiguous to the deep end of each of said first holes an anchor supporting an articular connective element, and inserting thereafter, so as to join with said anchor at said connective element, a strain data sensing probe having an end extending outside said hole whereby the longitudinal axes of said probes cross extensions of longitudinal axes of said second holes; affixing in each said second hole, substantially along said axis thereof, a beam having an end thereof extending outside said hole and disposed adjacent said outside probe extension; coupling each said adjacent beam and sensing probe ends outside their respective holes whereby each sensing probe is maintained stabilized with respect to said walls of said preexisting passage, and centered in said working face holes out of contact with the walls thereof, and reading signal outputs of said plurality of sensing probes as said excavation progresses to form a tunnel extension of said preexisting passage whereby the derivation of rock competence information on said tunnel walls is enabled and wherefrom support problems of subsequent excavations to further extend said tunnel walls can be anticipated.

Claim 4

An apparatus for measuring deformation in the medium defining a tunnel being excavated employing a plurality of deformation measuring mechanisms separately located in individual holes through said medium spaced around said excavation, each said mechanism comprising: an individual anchor affixed at the internal end of each one of said individual holes and each said anchor having a fixed connective component as an integral part thereof; a sensing probe situated in each one of said individual holes, said probe including a deformation sensing head, a tubular support element having an end inserted into said individual hole corresponding to said probe comprising said support element, and a part extending through and outside said corresponding individual hole, said sensing head being affixed at one end to said inserted end of said support element and having affixed on another end an operational element, said operational element having secured thereto, adjacent said another end of said sensing head, an arrangement of electrical strain gages, and attached to said operational element, at an end thereof extended toward said fixed connective component, a further connective component complementarily fitting together with said connective element; a means retained substantially rigid with respect to a stable surface adjacent said tunnel excavation working face, having attached thereto a coupling means wherein is securely attached said tubular support element whereby said sensing probe is maintained centered in said hole and out of contact with the surfaces thereof; and a means to read out strain data signals generated by said strain gages during said excavation.

Claim 5

An apparatus for measuring deformation in the medium defining a tunnel being excavated employing a plurality of deformation measuring mechanisms separately located in individual holes through said medium spaced around said excavation, each said mechanism comprising: an individual anchor affixed at the internal end of each one of said individual holes and each said anchor having a fixed connective component as an integral part thereof; a sensing probe situated in each one of said individual holes, said probe including a deformation sensing head, a tubular support element having an end inserted into said individual hole corresponding to said probe comprising said support element, and a part extending through and outside said corresponding individual hole, said sensing head being affixed at one end to said inserted end of said support element and having affixed on another end an operational element, said operational element having secured thereto, adjacent said another end of said sensing head, an arrangement of electrical strain gages, and attached to said operational element, at an end thereof extended toward said fixed connective component, a further connective component complementarily fitting together with said connective element; a means retained substantially rigid with respect to a stable surface adjacent said tunnel excavation working face, having attached thereto a coupling means wherein is securely attached said tubular support element whereby said sensing probe is maintained centered in said hole and out of contact with the surfaces thereof; and a means to read out strain data signals generated by said strain gages during said excavation.