Method for automatically driving gravel drain piles and execution apparatus therefor

An apparatus for driving gravel drain piles comprising:

• a casing raising device for raising a hollow casing which is vertically movably guided along a leader;
• a compaction rod driving device for vertically moving a compaction rod disposed within said casing and varying a period of upward and downward movement of said compaction rod;
• a compaction rod reaction detection device disposed halfway of said compaction rod to detect a reaction of the compaction rod and provide a value indicative thereof;
• a crushed-stone top end detection device for detecting a depth of a top end of crushed stones charged into said casing;
• a casing depth detection device for detecting an interpenetration depth of said casing;
• and processing means for comparing, after said casing has reached said predetermined depth and the charging of the crushed-stones has been confirmed, the detected value from said compaction rod reaction detection device with a set reaction value and determining a compacting degree of peripheral ground based-on said compared value, wherein said processing means is responsive to said crushed-stone top end detection device and a period of the compaction rod is controlled through the compaction rod driving device.

An apparatus for driving gravel drain piles comprising:

• a casing raising device for raising a hollow casing which is vertically movably guided along a leader;
• a compaction rod drive device for vertically moving a compaction rod disposed within said casing and varying an amplitude of upward and downward movement of said compaction rod;
• a compaction rod reaction detection device disposed halfway of said compaction rod to detect a reaction of the compaction rod and provide a value indicative thereof;
• a crushed-stone top end detection device for detecting a depth of a top end of crushed stones charged into said casing;
• a casing depth detection device for detecting an interpenetration depth of said casing;
• and processing means for comparing, after said casing has reached said predetermined depth and the charging of the crushed-stones has been confirmed, the detected value from said compaction rod reaction detection device with a set reaction value and determining a compacting degree of peripheral ground based on said compared value, wherein said processing means is responsive to said crushed-stone top end detection device and an amplitude of the compaction rod is controlled through said compaction rod driving device.

An apparatus for driving gravel drain piles comprising:

• a casing raising device for raising a hollow casing which is vertically movably guided along a leader;
• a compaction rod driving device for vertically moving a compaction rod disposed within said casing;
• a compaction rod height adjusting device for vertically moving said compaction rod driving device to vary a position of movement of the compaction rod into said hollow casing;
• a compaction rod reaction detection device disposed halfway of said compaction rod to detect a reaction of said compaction rod and provide a value indicative thereof;
• a crushed-stone top end detection device for detecting a depth of a top end of crushed stones charged into said casing;
• a casing depth detection device for detecting an interpenetration depth of said casing;
• and processing means for comparing, after the charging of the crushed stones has been confirmed, the detected value from said compaction rod reaction detection device with a set reaction value and determining a compacting degree of peripheral ground based on said compared value, wherein a height of an extreme end surface of the compaction rod is controlled through said compaction rod height adjusting device.

An apparatus for driving gravel drain piles comprising:

• a casing raising device for raising a hollow casing which is vertically movably guided along a leader and varying a raising speed of said casing;
• a compaction rod driving device for vertically moving a compaction rod disposed within said casing and varying a period of upward and downward movement and an amplitude of said compaction rod;
• a rod height adjusting device for vertically movably supporting said compaction rod drive device to vary a position of movement of said compaction rod into said hollow casing;
• a compaction rod reaction detection device disposed halfway of said compaction rod to detect a reaction of said compaction rod and provide a value indicative thereof;
• a crushed-stone top end detection device for detecting a depth of a top end of crushed stones charged into said casing;
• a casing depth detection device for detecting an interpenetration depth of said casing;
• and processing means for comparing, after said casing has reached said predetermined depth and the charging of said crushed-stones has been confirmed, the detected value from said compaction rod reaction detection device with a set reaction value and determining a compacting degree of peripheral ground based on said compared value, wherein said processing means is responsive to said crushed-stone top end detection device and said casing depth detection device and at least one of a raising speed of the casing, a period of the compaction rod, an amplitude of the compaction rod and a height of an extreme end surface of the compaction rod are controlled through said casing raising device, said compaction rod driving device and said compaction rod height adjusting device.

A method for automatically driving gravel drain piles comprising the steps of:

• interpenetrating a hollow casing to a predetermined depth into a relatively loose sand layer saturated with water;
• raising the casing while tamping crushed-stones charged into said casing by a compaction rod disposed within said casing;
• driving gravel drain piles at regular intervals within the sand layer while continuously performing the steps of raising the casing and tamping the crushed-stones by the compaction rod;
• detecting a magnitude of a crushed-stone tamping reaction by a reaction detecting device provided on said compaction rod and providing a real reaction value;
• comparing the real reaction value with a set reaction value which is set in correspondence to the condition of the ground;
• controlling a raising speed of the casing in response to said compared value so as to increase, decrease or make constant the raising speed of the casing;
• determining a compacting degree of peripheral ground based on said compared value;
• and
• compacting the peripheral ground.

A method for automatically driving gravel drain piles comprising the steps of:

• interpentrating a hollow casing into a predetermined depth into a relatively loose sand layer saturated with ground water;
• raising the casing while tamping crushed stones charged into said casing by a compaction rod disposed within said casing;
• driving gravel drain piles at regular intervals within the sand layer while continuously performing the steps of raising the casing and tamping the crushed-stone by the compaction rod;
• detecting a magnitude to a crushed-stone tamping reaction by a reaction detecting device provided on the compaction rod and providing a real reaction value;
• comparing the real reaction value with a set reaction value which is set in correspondence to the condition of the ground;
• controlling at least one of a raising speed of the casing, a period of the compaction rod, an amplitude of the compaction rod and a height of an extreme end surface of the compaction rod in response to said compared value;
• determining a compacting degree of peripheral ground based on said compared value;
• and
• compacting the peripheral ground.