According to the data analysis of a 20 years long monitoring work, the Locality 1Archaeological Site of Zhoukoudian has been threatened by severe hazards as wind and rain erosions, weathering, crumbling and instability, etc. After the severe rain storm on 21st July 2012， water catchment was discovered at the bottom and the west section of the cave and soon disappeared. Through geophysical prospecting, large fissures and fracture zones were found at the bottom of the cave, which endangered the overall stability of the site.
The plan of a new protective shelter was reported to the World Heritage Centre of UNESCO by the State Administration of Cultural Heritage of China in August 2013. ICOMOS approved the project in November 2013 in the replying letter. The construction drawings were finished in November 2014 with prude and full consideration. The construction work commenced in May 2015 and completed in August 2018. The shelter was open to public in September 2018.
The protective shelter was designed to prevent the site from rain, snow, hail and other threatening factors. A mild and gradual conservation strategy was applied that the violent vibration of wind temperature and humidity be reduced by the shelter, while the site still connected to its original natural environment.
A principle of minimal and reversible interventions was applied on the project. The single layer reticulated shell structure of large span, which shelters the Peking man Cave site, is supported by the two rows of footholds situated on the peak of the hill on the south and at the foot on the north, to cover a least necessary area of the cave and to keep away from the site per se and its precipice. The footholds were situated on the flat rock formation. All the components of the shelter were prefabricated and assembled on site to keep the disturbance on the site during construction work to the minimal extent, and to ensure the possibility of dismantling in future to restore the environment to its original condition.
The morphology of the mountain before the collapsing of the Peking Man Cave was deduced from clues as contour lines of the current landform to shape the overall form of the shelter. The new structure was consequently able to blend with its immediate surroundings morphologically. A green roof was designed as the outer skin of the shelter, which would hide itself into the woods after two years of properly growing up as expected. Meanwhile, the inner skin of the shelter imitates the rock surfaces inside the cave to remind the visitors of the geography of the archaeological site.
The irregular curved surface of space single reticulated shell structure covers an area of about 3700 m2. The east-west span is 54.5m and the north-south 77.5m. The height difference between the two rows of footholds is 30.7m, while the maximum height of the shelter from the ground outside is 35.7m.
The double-skin creates a buffering layer to alleviate the abrupt changes of natural factors including temperature and humidity. The blades of the skin were generated by parametric calculations on computer, which overlap closely with one another to realize an organized drainage of rainwater, while providing daylight of uniformity and mild ventilation There are 825 blades in all, of which 420 blades are on the outer skin and 405 on the inter skin.
Base on the meteorological monitoring data of micro-environment in Peking Man Cave, analog computations were conducted through numerical wind tunnel techniques, to simulate the height of the shelter, gaps between blades, temperature, humidity, daylight, ventilation and other variates. The results provided evidences of design efficiency, and assisted architects to develop a scientific and reasonable programme.
The precipice of Peking Man Cave is employed as display platform. Information of excavation process is displayed on the west side, while the historical backgrounds and research findings are explained on the north side through multimedia technologies. The immersive experience would impress the visitors of the significance of this site and explain the information to the best effect.