Apparatus for forming a liquid-tight seal across gaps formed between at least first and second adjacent mats in a load-supporting surface includes at least one seal member configured to be coupled to each among first and second outer edges of at least a first side of each among at least first and second adjacent mats and extend laterally outwardly therefrom into one among at least two gaps formed between the adjacent mats and abut at least one other such seal member extending into the same gap from the other adjacent mat that forms the gap.

A system for strengthening a sloped structure comprises first and second opposing sides, a bottom side, fill material, a plurality of facing baskets adjacent the first side, a plurality of reinforcing members disposed within the fill material, and an impermeable membrane. The second side is adapted to be adjacent the sloped structure. The bottom side adjoins bottom edges of the first and second sides, thereby forming a cavity within the first, second, and bottom sides. The fill material is disposed within the cavity. The impermeable membrane encapsulates at least a portion of the fill material and one or more of the reinforcing members. The facing baskets and the reinforcing members are positioned in a plurality of layers, with each layer comprising one facing basket and one corresponding reinforcing member. The impermeable membrane is positioned to span two or more layers of the plurality of layers.

A system for reinforcing and facing a wall comprises a plurality of facing baskets and corresponding substantially horizontal reinforcing members, arranged in a plurality of layers. An impermeable membrane is positioned to uninterruptedly span two or more layers. At each of one or more layers, a portion of the impermeable membrane is positioned around the outer end of the corresponding reinforcing member.