Sains Malaysiana 46(11)(2017): 2041-2048

http://dx.doi.org/10.17576/jsm-2017-4611-04

Failure Characteristic and Fracture Evolution Law of Overburden of Thick Coal in Fully Mechanized Sub-level Caving Mining

(Pencirian Kegagalan dan Evolusi Retakan Hukum Beban Atas Arang Batu Padat dalam Perlombongan Perampakan Subparas Berjentera Penuh)

XIAOLEI WANG^1,2, QIRONG QIN¹ & CUNHUI FAN¹*

¹State Key Laboratory of Oil & Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu 610050, China

²Heilongjiang Vocational College of Energy, Shuangyashan 155100, China

Diserahkan: 30 Januari 2017/Diterima: 12 Mei 2017

ABSTRACT

In mining process, the height of water flowing fractured zone is important significance to prevent mine of water and gas, in order to further research the failure characteristic of the overlying strata. Taking certain coal mine with 5.82 m mining height as the experimental face, by using the equipment which is sealed two ends by capsules in borehole, affused measurable water between the two capsules and borehole televiewer system, ground penetrating radar, microseismic monitoring system in underground coal mine, the height of water flowing fractured zone of fully-mechanized top caving are monitored, a numerical simulation experiment on the failure process was conducted, a similarity simulation experiment on the cracks evolution was conducted, at the same time, empirical formula of traditional was modified, The results showed that the height of caving and fractured zones were respectively 43.1 and 86.7 m in fully mechanized sub-level caving mining. The data difference of each test method of caving, fractured and water flowing fractured zones were respectively less than 4.5%, 7.1% and 9.0%. The degree of fracture development was low before mining, the number of fissures was obviously increased after mining, the degree of fracture development increased. The fractures cluster region mainly focuses near the coal wall. The fractures density distribution curves of overlying strata like sanke-shapes. The new and adapt to certain coal mine geological conditions empirical formula of water flowing fractured zone height is proposed.

Keywords: Cracks evolution; empirical formula; ground penetrating radar; microseismic monitoring system; overburden failure

ABSTRAK

Dalam proses perlombongan, zon retak ketinggian air mengalir adalah keertian penting untuk mengelakkan lombong daripada air dan gas untuk kajian lanjut tentang ciri kegagalan strata atas. Dengan mengambil lombong arang batu tertentu pada ketinggian lombong 5.82 m sebagai muka uji kaji, menggunakan peralatan yang ditutup kedua-dua hujung dengan kapsul dalam lubang gerek, pelakuran air boleh ukur antara dua kapsul tersebut dan sistem petelelihat lubang gerek, radar menembusi tanah, sistem pemantauan mikroseismos lombong arang batu bawah tanah, zon retak ketinggian air mengalir perampakan atas berjentera penuh adalah dipantau, uji kaji simulasi berangka ke atas proses kegagalan telah dijalankan, uji kaji simulasi keserupaan pada evolusi retak telah dijalankan dan pada masa yang sama formula empirik tradisi telah diubah suai. Keputusan kajian menunjukkan bahawa ketinggian zon perampakan dan retak masing-masing adalah 43.1 dan 86.7 m dalam perlombongan perampakan subparas berjentera penuh. Perbezaan data untuk setiap kaedah ujian zon perampakan, zon retak dan zon retak air mengalir masing-masing kurang daripada 4.5%, 7.1% dan 9.0%. Tahap pembangunan retak adalah rendah sebelum perlombongan, bilangan rekahan jelas meningkat selepas perlombongan serta darjah pembangunan retak juga meningkat. Rantau kelompok retak tertumpu berhampiran dinding arang batu. Lengkung taburan kepadatan retak atas strata berbentuk seperti sanke. Kaedah baru dan sesuai dengan formula empirik keadaan geologi lombong arang batu tertentu zon retak ketinggian air mengalir adalah dicadangkan.

Kata kunci: Evolusi retak; formula empirik; kegagalan beban atas; radar menembusi tanah; sistem pemantauan mikroseismos

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