建议将腰鼓形人孔改为长方形人孔沈海坚８０年代以来，我国大力推广全塑市话电缆。由于全塑电缆具有重量轻、耐拉、耐磨、耐腐蚀、摩擦力小、可作长距离布放等优点，所以，国内已基本上摒弃了铅皮电缆。但全塑电缆可塑性差，有反弹力，若用腰鼓形人孔，因人孔侧壁是曲面形... It is recommended that the waist drum-shaped manhole be replaced by a rectangular manhole Shen Haijian Since the 1980s, China has vigorously promoted all-plastic telephone cable. As all-plastic cable with light weight, resistance to pull, wear-resistant, corrosion-resistant, small friction, for long-distance deployment, etc. Therefore, the domestic has largely abandoned the lead-skin cable. However, all-plastic cable plasticity is poor, there is rebound, if the waist drum-shaped manhole, the manhole sidewall is curved ...