KaraKoram Highway (KKH), located in North Pakistan, is the only vital land communication line between Pakistan and China and also the international highway with the highest average elevation in the world. It is considered as the Eighth Wonder of the World and one of the 17 most costly construction projects in modern times in the world.
Karakoram Highway Improvement Project runs 335km long from Raikot to Khunjerab. It was designed and constructed according to the Chinese standard for third-grade highways. Its construction started in August 1, 2008 and was successfully completed in November 30, 2013.
In 2010, a large landslip happened on the bank of HUNZA River in North Pakistan, causing a barrier lake. And this barrier lake inundated KKH Highway under construction for over 20km. Therefore, CRBC and Pakistan National Highway Authority signed the supplementary agreement on the Realignment of KKH at Attaabad Barrier Lake.
The Realignment of KKH at Attaabad Barrier Lake is 24km long, and the construction started on July 26, 2012. The main works included five tunnels (7136.8m) and two bridges (471.8m). The completion ceremony of this project was held on September 14, 2015. By then, the northern section of KKH had been fully completed.
It is not only the only land corridor between China and Pakistan, but also a friendship road between China and Pakistan. It does not only greatly improve the main highway network of Pakistan, but also lays a good foundation for the interconnectivity of China-Pakistan Economic Corridor.
In order to solve the problem of supply of main materials after the barrier lake was formed, the project department built several temporary wharfs and purchased large barges to transport the construction materials.
Because of developmental joint fissure of rocks along the line and the broken rocks, coupled with the steep mountains, collapse may happen with the action of gravity. For general collapses, subgrade protection, slope cleanup and setting of blocking structures were adopted. For some very serious sections, tunnels or tunnel sheds were built.
In order to cope with the problem of short construction time, low temperature and everlasting snow in winter, the project department established Khunjerab Plateau Commando, Khunjerab Snow Slid Rescue Commando and so on, and held labor competition to enhance the working efficiency.
In order to solve the problem of high-altitude perennial frozen soil, the project constructors observed and tested the freezing and thawing characteristic of the frozen soil all year round. Through adding high-strength Geogrid to the top layer of the subgrade and adopting the construction technology ballast ventilation embankment, they basically solved the influence of frozen soil on the subgrade settlement.
Washout selection is mainly located at the Sust- K796 valley line deep-cutting gorge section. The project department adopted such design schemes as raising the subgrade, setting up bank protecting wall, wire gabion and spur dike.
On August 15, 2008, the original Gilgit Bridge collapsed, which was the only passage in Gilgit. Its blockade undoubtedly brought great difficulties to the project construction, especially the production and life of local people. The project department made the field investigation at the top speed, determined the place to build the steel temporary bridge, imported steel temporary bridge from China and completed the erection of the bridge in November of that year.
In November, 2008, the river water which rose suddenly in Pasu Town, Bagurmit, washed out the farmland of the villagers. The project department decided to transfer two excavators to dredge the river channel to protect the villagers’ farmland. And the villagers voluntarily make the bilingual banner “Improving the Channel, Benefiting Local People” to the project department.
Because of temporary pass opening, CRBC people gave up the opportunity to gather with their family members but rushed to the front line of keeping the road smooth and clearing the danger. It was because of their spirit of “sacrifice” that they successfully completed the task of keeping the road smooth, and the relief materials, living guarantee and “food” of villagers were smoothly transported to the site.
Along KKH project, there are many snow mountains and the melt flowing snow water provides convenience for hydroelectric power for the villages along the line. But, the power station channel and shortcuts the villagers themselves built were simple and crude. As long as the temperature was high, the sediment in the snow water would block the channel and the water level would rose to wash out the shortcuts, which was very inconvenient. In order to help the local villagers to solve the actual problems, the project department sent people and machines to repair the shortcuts of the power station and dredge the water supply channel.
On January 4, 2010, the great landslide really brought a great test to the project construction. What was worse, the large-area barrier lake endangered the life and property safety of the Pakistan people. The project department established several groups, including emergency rescue group, transfer group, dredging group and observation group, and spared no effort to rescue the Pakistan people in trouble.