to strenghten; to add padding to; to prop up with a cushion

Link to present incidents:
A project aims to investigate the social case for gardens and what impact they have on health and well-being. (…) Nearly one in four front gardens in the UK is completely paved over." Participating in this research, in terms of the wider picture, everyone will be part of what can hopefully be - depending on the results, of course - part of the evidence needed to bolster the social case for more green spaces and gardens in cities." BBC website