2018 China International Garden Expo was held in Nanning, positioned along a river in the city’s hilly outskirts. Interspersed in the southeast section of the site is a series of quarries. The organizing committee hoped to transform seven of the relatively intact quarries into distinctive gardens displaying in the garden expo. The site covers an area of about 33 hectares. Several years had passed since mining at some of the quarries onsite ceased, yet two of the quarries persisted mining activities until the city won the expo bid. These quarries suffered blasting during the mining that caused fragmented surfaces and rugged landforms at pit bottom. The site was strewn with dilapidated hills, towering cliffs, deserted land surfaces, bottomless ponds, piles of abandoned soil and gravel, rusty quarrying equipment, etc.

▼项目概览，general view

The project faces a series of huge challenges：1. The quarries presented extremely complex landforms that imposed design challenges in accordance to current mapping images. 2. Water levels in the quarries were unstable. In fact, two of the quarries that stopped mining later showed sustained rising water levels. Very limited valid hydrological data were available. 3. The geological conditions of the quarries were complex and the cliffs were dilapidated. The possibility of collapse and rock fall present unpredictable safety risks. 4. The quarries’ ecological environment was severely damaged and the restoration of vegetation was faced with great challenges.

▼现状条件，Site Context

Through an aerial scanning of UAV, landscape architects obtained three-dimensional digital models of all quarries, on this basis the design could well match the site landforms. To provide relevant data required for the design, a local institution was assigned to record changes in the water levels of each quarry every half month. With safety as primary consideration, the setting of facilities and various paths intentionally avoid dangerous zones, while highlighting distinctive features of the quarry landscape. Moreover, safety measures were strictly implemented where necessary to prevent cliff-slide rock falls. According to the different goals of vegetation restoration, soil was introduced to earth up planting areas forming different soil thicknesses to create conditions for habitat restoration of the particularly large number of native plant species. Stones, gravels, mucks, and mining machines on the site are reasonably preserved and reused in the new landscape. Although similar in appearance, the quarries vary from each other greatly in terms of scale, space structure, and characteristics. Landscape architects adopted various methods of intervention and vegetation restoration that complement each quarry’s distinctive qualities.

1号采石场（落霞池）

Quarry No. 1

Quarry No. 1 is a one-hectare quiet pond walled within a rough rock hedge, in which China’s traditional landscape aesthetics is attempted to be embodied. A wooden and irregularly-shaped pavilion is nestled within a rock gap at the edge of a pond, whose structural form is inspired by the local vernacular architecture.