A.当管径≤400mm时基材厚度≥1.2mm
B.当管径≤400mm时基材厚度≥1.0mm
C.当管径>400mm时基材厚度≥1.5mm
D.当管径>400mm时基材厚度≥2.0mm
A.1.0,2
B.1.5,3
C.2,3
D.3,4
根据气力输送的特点,降低动力消耗,节约能源是一个重要的研究课题,从经验中知,管道内径是关于能耗的重要参数。直观上看,当输送量一定时,管径过小,输送易阻滞,管径过大,虽输送畅通,但又造成能量的浪费。根据经验,把管径分成三组,各组的试验结果如下表所示,试用方差分析法比较各组的效果.
管径(mm) | 单位功耗 |
230 | 0.0308,0.0476,0.0504 |
250~260 | 0.0532,0.032,0.0218,0.028,0.028, 0.042,0.0336,0.042,0.042,0.028 |
280~320 | 0.07,0.07,0.0644,0.0312,0.0756,0.0756, 0.07,0.0588,0.0588,0.042,0.0308,0.0364, 0.0448,0.21,0.154,0.1064,0.1288,0.112, 0.1064,0.1288,0.0756,0.0644,0.0504,0.0644, 0.0504,0.0308 |
B、声测管管口应高出桩顶100mm-300mm,且各声测管管口高度应一致
C、《公路工程基桩动测技术规程》(JTG/TF81-01-2004)规定、桩径D不大于1600mm时,埋设三根管:当桩径大于1600mm时,应埋设四根管
D、《建筑基柱检测技术规范》(IGJ106L-2014)规定、柱径小于或等于800mm时,不少于2根声测管,桩径大于800mm且小于或等于1600mm时,不少于3根声测管:桩径大于1600mm时,不少于4根声测管:桩径大于2900mm时,宜增加预埋声测管数量
A.70
B.80
C.90
D.100