Objective Due to the limited space available at the shield launching site. the restricted size of the reaction frame cannot provide sufficient shield launching reaction force on its own. Therefore. it is necessary to design and install a back-support structure for the reaction frame to achieve synergistic stress between the two. https://www.markbroyard.com/hot-sale-us-topo-7-5-minute-map-for-sunken-lake-mi-supply-limited-grab/