Monitoring and forewarning method for coal-rock dynamic disasters based on electromagnetic radiation and earth sound
A monitoring and forewarning method for coal-rock dynamic disasters based on an electromagnetic radiation and an earth-sound monitoring includes the following steps: (1) calculating the weighted average value of research parameter P(t) during a time period according to the monitoring data collected by the electromagnetic radiation and the earth-sound monitoring system in real time; (2) calculating D(t), the deviation value of P(t); (3) calculating |D(t)| as the deviation threshold value, the average value of |D(t)| during period of normal mining of the working surface; (4) calculating D S , the number of times that D(t) is greater than |D(t)| in one day; (5) normalizing D S to obtain the monitoring and forewarning index ε; (6) forewarning the hazard state of dynamic disaster of the working surface in real time according to ε and forewarning method, determining hazard level.
1. A monitoring and forewarning method for coal-rock dynamic disasters based on an electromagnetic radiation and an earth sound, wherein an electromagnetic radiation sensor and an earth-sound sensor are respectively arranged on a coal body or a rock body for collecting an energy and a pulse number of the electromagnetic radiation, and an energy and a frequency of an earth-sound signal in real time as original data; the method comprises the following steps:
step (1), calculating P(t), wherein the P(t) is a weighted average value of a research parameter in a time period, and the P(t) is calculated according to monitoring data collected by an electromagnetic radiation and an earth-sound monitoring system;
step (2), calculating D(t), wherein the D(t) is a deviation value of the P(t);
step (3), calculating |D(t)| , wherein the |D(t)| is an average value of the |D(t)|, and the |D(t)| is an absolute value of the D(t) during a period of normal mining of a working surface, and using the |D(t)| as a deviation threshold value;
step (4), calculating D S , wherein the D S is a number of times that the deviation value D(t) is greater than the deviation threshold value |D(t)| in one day;
step (5), normalizing the D S to obtain a monitoring and forewarning index ε;
step (6), forewarning a hazard state of a dynamic disaster of the working surface in real time according to the ε and a forewarning method, and determining a hazard level of the dynamic disaster,
wherein, in the step (1), the research parameter is one or more of an electromagnetic radiation energy, an electromagnetic radiation pulse number, an earth-sound energy, or an earth-sound frequency, and the weighted average value of the research parameter P(t) is a result of a cumulative sum of the research parameter divided by a time window length during the time period,
the monitoring and forewarning index ε in the step (5) is calculated by the following formula:
ɛ
=
D
S
-
D
S
-
min
D
S
-
max
-
D
S
-
min
,
wherein D S-max is a maximum value of the D S during the time period, and D S-min is a minimum value of the D S during the time period, and
the hazard level in the step (6) includes no hazard, a low hazard, a medium hazard and a high hazard; and the hazard level is determined as follows: when ε<0.5, no hazard exists, when 0.5≤ε<0.65, the low hazard exists, when 0.65≤ε<0.8, the medium hazard exists, and when 0.8≤ε, the high hazard exists.
2. The monitoring and forewarning method of claim 1 , wherein, the time period is 10 minutes.
3. The monitoring and forewarning method of claim 1 , wherein, the deviation value D(t) in the step (2) is calculated by the following formula:
D
(
t
)
=
P
(
t
)
-
P
(
T
t
)
_
P
(
T
t
)
_
;
wherein,
P
(
T
t
)
_
=
1
n
∑
i
=
1
n
P
i
(
T
t
)
,
T
t
represents a time interval related to time t, and is the time interval from a time point before the time t to the time t, and n is a number of the P(t), the weighted average value of the research parameter, in the time interval of T t .
4. The monitoring and forewarning method of claim 3 , wherein, the time interval is 24 hours.
5. The monitoring and forewarning method of claim 1 , wherein, the period of normal mining of the working surface in the step (3) is a period in which the working surface is not affected by geological structures including faults and folds and there is no abnormal situation in the working surface including a roof weighting and a dynamic pressure behavior, and the period is one or multiple months.
6. The monitoring and forewarning method of claim 1 , wherein, the time period is from a time point that a previous dynamic pressure behavior occurs to a present time point.