Device for real-time monitoring movement trajectory of mine roof strata and method thereof

A device for real-time monitoring a movement trajectory of mine roof strata, comprising supporting pipes, connecting pipes, a displacement sensor, an angle sensor, a hole sealing ring, a grouting main pipe, a grouting branch pipe, a grouting unit, and a data acquisition unit;

• the supporting pipes are made of hard materials, the connecting pipes are made of soft materials and the connecting pipes are capable of being compressed, extended, or bent by an external force;
• a plurality of supporting pipes are connected end-to-end in sequence, and two adjacent supporting pipes are connected to each other by the connecting pipes;
• between two adjacent supporting pipes, at least one of the supporting pipes is provided with the displacement sensor for measuring a distance between two adjacent supporting pipes;
• each of the supporting pipes is provided with one angle sensor, and the angle sensor is used to measure an angle of each of the supporting pipes where the angle sensor is located;
• at least one hole sealing ring is arranged in a circumferential direction of a head end and a tail end of each of the supporting pipes;
• a grouting main pipe passes through an interior of each of the supporting pipes and the connecting pipes, at least one grouting branch pipe is installed inside each of the supporting pipes, one end of the grouting branch pipe is communicated with the grouting main pipe, an other end of the grouting branch pipe is exposed from a side wall of the supporting pipe, and the other end of the grouting branch pipe is located between two hole sealing rings;
• a grouting unit is connected to the grouting main pipe for injecting grout into the grouting main pipe;
• and
• a data acquisition unit is in signal connection to the displacement sensor and the angle sensor for collecting distances and angle data;
• the device is configured to perform a method for real-time monitoring the movement trajectory of mine roof strata, wherein the method comprises the following steps:
• step 1, drilling a hole in a roof strata of a roadway or a working face to form a monitoring borehole;
• step 2, pushing the sequentially connected support pipes and the connecting pipes into the monitoring borehole, and the hole sealing ring is attached to the supporting pipes and an inner wall of the monitoring borehole;
• step 3, injecting grout from the grouting unit into the grouting main pipe and the grouting branch pipe, the grout flows to the supporting pipes, the inner wall of the monitoring borehole, and a space between two the hole sealing rings;
• after the grouting is completed and before the grout solidifies, removing the grouting main pipe from the monitoring borehole;
• step 4, after the grout solidifies, collecting, by the data acquisition unit, a distance data measured by the displacement sensor and an angle data measured by the angle sensor in real time, and then obtaining a horizontal position and a vertical position of any of supporting pipes in real-time, and depicting the movement trajectory of roof strata based on the horizontal position and the vertical position of each of supporting pipes in real-time;
• a calculation formula for the horizontal position Xn of any of supporting pipes is:
• X
• n
• =
• I
• ⁢
• cos
• ⁢
• α
• 1
• +
• d
• 1
• +
• I
• ⁢
• cos
• ⁢
• α
• 2
• +
• d
• 2
• ⁢
• …
• +
• d
• (
• n
• -
• 1
• )
• +
• 1
• 2
• ⁢
• I
• ⁢
• cos
• ⁢
• α
• n
• ;
• in the calculation formula:
• l—a length of the supporting pipe, in cm;
• α1—an angle of a first supporting pipe measured by the angle sensor, in degrees;
• α2—an angle of a second supporting pipe measured by the angle sensor, in degrees;
• αn—an angle of a nth supporting pipe measured by the angle sensor, in degrees;
• d1—a projection value of a distance between the first supporting pipe and the second supporting pipe in a X direction measured by the displacement sensor, in cm;
• d2—a projection value of a distance between the second supporting pipe and a third supporting pipe in the X direction measured by the displacement sensor, in cm;
• d(n-1)—a projection value of the distance between a (n−1)th supporting pipe and the nth supporting pipe measured by the displacement sensor in the X direction, in cm;
• a calculation formula for a vertical position of any of supporting pipes is:
• Y
• n
• =
• I
• ⁢
• sin
• ⁢
• α
• 1
• +
• h
• 1
• +
• I
• ⁢
• sin
• ⁢
• α
• 2
• +
• h
• 2
• ⁢
• …
• +
• h
• (
• n
• -
• 1
• )
• +
• 1
• 2
• ⁢
• I
• ⁢
• sin
• ⁢
• α
• n
• ;
• l—a length of supporting pipe, in cm;
• α1—an angle of the first supporting pipe measured by the angle sensor, in degrees;
• α2—an angle of the second supporting pipe measured by the angle sensor, in degrees;
• αn—an angle of the nth supporting pipe measured by the angle sensor, in degrees;
• h1—a projection value of a distance between the first supporting pipe and the second supporting pipe in a Y direction measured by the displacement sensor, in cm;
• h2—a projection value of a distance between the second supporting pipe and the third supporting pipe in the Y direction measured by the displacement sensor, in cm;
• h(n-1)—a projection value of a distance between a (n−1)th supporting pipe and the nth supporting pipe in the Y direction measured by the displacement sensor, in cm.