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　　（1）分段的長(zhǎng)度必須符合作業(yè)規(guī)程或補(bǔ)充措施規(guī)定，但不得小于15米；

　�。�2）分段開(kāi)口應(yīng)選在頂板較好，支架完整的安全地點(diǎn)；

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