约束区 meaning in English

confining region

In the dam foundation restraint area , mgo can be mixed into concrete to prevent dam longitudinal crack . research on autogenous volume change of rcc mixed with mgo , and research on thermal stress compensation of darn foundation prove that rcc mixed with mgo plays a role in dam crack control
在材料措施方面，深入研究高碾压混凝土坝基础约束区采用外掺mgo措施，利用其微膨胀性能补偿坝体降温过程中产生的温度应力，以防止大坝纵向裂缝的发生。