较高的拱有利于巷道围岩稳定和支护结构受力,但断面利用不好。
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较低的拱不利于巷道围岩稳定和支护结构受力,但断面利用较好。
A. 对
B. 错
在曲线段,矿车车体的中心线和线路的中心线不相吻合,会发生矿车外边角外伸和矿车内侧车帮内移现象。
A. 对
B. 错
梯形巷道无运输设备的净宽:净高1/2处的宽度
A. 对
B. 错
Discusswithyourclassmateswherethereareanyproblemsinthefollowingletterandhowyoucanimproveit.Thencontrastyourimprovedletterwiththeoriginalone.DearSirs:Referringtoourletter,wewishtocallyourattentiontothefactthatuptothepresentmomentnonewshascomefromyouabouttheshipment.Asyouhavebeeninformedinoneofourpreviousletters,theusersareinurgentneedofthemachineandinfactpressingusforanearlydelivery.Undersuchcircumstances,itisimpossibleforustoextendL/Cagain.Wefeelitourdutytoremindyouofthismatter.Whenwillyoubereadytoshipthegoods?Yoursfaithfully,AlexWang