渠道衬砌混凝土裂缝产生的原因分析及预防措施

南水北调中线京石段渠道机械衬砌已进入施工高峰期，渠道衬砌为大面积薄板混凝土结构，在硬化过程和硬化后都会因混凝土干缩、温度变化及地基沉降等产生不同程度的裂缝。而混凝土面板的结构型式、边界条件等比其它混凝土结构存在有较大的差异，这种差异使面板裂缝受混凝土风缩、干缩、温度变化及地基沉降的影响更大，容易产生裂缝，从施工过程上讲，裂缝的产生与混凝土衬砌时的施工环境、削坡的质量、切缝时间的掌握及混凝土养护等几个因素有关。

The cause and preventative measures of cracks in canal lining concrete

The canal lining work of the middle-Jingshi line of south-to-north water diversion project hasentered the peak construction period. However, as the canal lining is composed of large sheet of concrete, cracks will occur during or after the hardening process, due to concrete shrinkage, temperature changes and the foundation settlement. Moreover, the structure, boundary conditions of this concrete slab are quite different from other concrete structures, which makes it liable to concrete shrinkage, temperature changes and the foundation settlement. As to the construction process, the occurrence of cracks is related to the construction environment, the quality of slope cutting, the timing of cutting slot, the maintenance of the concrete, etc.