China builds a bridge across the sky

The chal­leng­ing Sichuan-Ti­bet line will run for 1,700 kilo­me­ters over breath­tak­ing but dan­ger­ous ter­rain and will cost a stag­ger­ing $36.88bn

China Daily (Hong Kong) - - BUSINESS -

CHENGDU — Breath­tak­ing scenery and breath­tak­ing dan­gers. Chi­nese engi­neers will face both as they em­bark on build­ing the world’s most dif­fi­cult rail­way.

The Sichuan-Ti­bet line will be the sec­ond rail­way into South­west China’s Ti­bet au­ton­o­mous re­gion af­ter the Qing­hai-Ti­bet con­nec­tion.

It will go through the south­east of the Qing­hai-Ti­bet Plateau, one of the world’s most ge­o­log­i­cally ac­tive ar­eas.

“The con­struc­tion and op­er­a­tion of the Sichuan-Ti­bet Rail­way will have to over­come the big­gest risks in the world,” said You Yong, chief en­gi­neer of the In­sti­tute of Moun­tain Haz­ards and En­vi­ron­ment of the Chi­nese Academy of Sci­ences, who is lead­ing a sci­en­tific and tech­no­log­i­cal sup­port team to avoid dis­as­ters in the moun­tains.

China Rail­way Eryuan En­gi­neer­ing Group Co Ltd, which is de­sign­ing the line, re­vealed that it will run from Chengdu, cap­i­tal of South­west China’s Sichuan prov­ince, through Ya’an and Kangding, and en­ter Ti­bet via Qamdo.

It will then go through Ny­ingchi and Shan­nan pre­fec­tures be­fore ar­riv­ing at Lhasa, cap­i­tal of Ti­bet. The to­tal con­struc­tion length will be about 1,700 kilo­me­ters and it will cost 250 bil­lion yuan ($36.88 bil­lion)

Al­ready dubbed an epic jour­ney, the Sichuan-Ti­bet Rail­way is a key project for China’s 13th Five-Year Plan from 2016 to 2020. It will climb from the Sichuan Basin sev­eral hun­dred me­ters above sea level to the “Roof of the World”, at an al­ti­tude of more than 4,400 me­ters.

Xia Lie, a se­nior en­gi­neer at China Rail­way Eryuan En­gi­neer­ing Group, de­scribed it as a huge “roller coaster” through risky ter- rain of moun­tains and canyons.

It will go through eight as­cents and de­scents, and more than 80 per­cent of the line will be bridges.

“The cu­mu­la­tive as­cent of the Sichuan-Ti­bet Rail­way will ex­ceed 16,000 me­ters, tun­nels and which is equiv­a­lent to dou­ble the height of Qo­molangma, (also known as Mount Ever­est in the West) the world’ s high­est moun­tain,” said Xia.

“It will be the most dif­fi­cult su­per project in rail­way con­struc­tion his­tory.”

Con­struc­tion has be­gun on the two ends of the rail­way. The sec­tion be­tween Chengdu and Ya’an is ex­pected to open in June 2018.

The fea­si­bil­ity study on the sec­tion be­tween Ya’an and Kangding has been com­pleted. The sec­tion be­tween Lhasa and Ny­ingchi is un­der con­struc­tion.

But the sec­tion from Kangding to Ny­ingchi — the most dif­fi­cult and the long­est sec­tion — is still un­der de­sign. Its con­struc­tion is ex­pected to be­gin in 2019 and could take about seven years, ac­cord­ing to Xia.

The Sichuan-Ti­bet con­nec­tion will be a ma­jor line in the western China rail net­work, link­ing Ti­bet and more de­vel­oped cen­tral and eastern re­gions. The de­sign speed is from 160 kilo­me­ters per hour to 200 kilo­me­ters per hour.

On com­ple­tion, the travel time by train from Chengdu to Lhasa will be cut from 48 hours to about 13 hours.

Xia con­firmed that ex­perts con­ducted a sci­en­tific study of the key tech­nolo­gies needed for the con­struc­tion in May 2016.

When the team ar­rived at a town in Ti­bet’s Markam county, all the peo­ple turned out to present them with

pieces of silk given as greet­ings, and but­tered tea, and ex­pressed the wish to see the rail­way built as early as pos­si­ble.

With white snow capped moun­tains, crys­tal glaciers, steep moun­tains and deep canyons, the Sichuan-Ti­bet Rail­way will string to­gether beau­ti­ful vis­tas, but with hid­den dan­ger.

You Yong, who has spent al­most 30 years study­ing moun­tain haz­ards, said the line will tra­verse the eastern Q in­g­hai-Ti­bet Plateau, which has sharp changes in ter­rain.

“It will go over 21 snow­capped moun­tains more than 4,000 me­ters high and cross 14 ma­jor rivers. The re­gion is full of steep slopes and deep val­leys,” You said.

The ac­tive ge­o­log­i­cal struc­ture of the re­gion causes strong earthquakes. The rail­way will go through quake zones such as the Long­men Moun­tain and Yar­lung Zangbo River seis­mic belts, You pointed out.

The mag­ni­tude-8 earth­quake that dev­as­tated Sichuan’s Wenchuan county i n 2008 caused great en­vi­ron­men­tal dam­age and de­stroyed count­less roads. The quake caused moun­tain haz­ards such as land­slides and de­bris flows.

You stressed that the Sichuan-Ti­bet Rail­way has four ma­jor en­vi­ron­men­tal char­ac­ter­is­tics: sig­nif­i­cant ter­rain el­e­va­tion dif­fer­ences, strong plate ac­tiv­i­ties, fre­quent moun­tain dis­as­ters and a sen­si­tive eco­log­i­cal en­vi­ron­ment.

Moun­tain haz­ards were a ma­jor chal­lenge. “The re­gions along the SichuanTi­bet Rail­way have the most de­vel­oped, most ac­tive, most di­verse and most se­ri­ous moun­tain haz­ards in China,” You said.

For in­stance, there are 399 haz­ard sites i n the re­gion along the Par­lung Zangbo River in Ti­bet, re­garded as one of the most dan­ger­ous road sec­tions in the world. The fre­quent haz­ards block roads.

Dan­gers along the rail­way route in­clude land­slides, de­bris flows, and snow and ice dam­age. The land­slides mainly hap­pen in the alpine gorges of the Heng­duan Moun­tains and south­east­ern Ti­bet.

This sec­tion could suf­fer from the most con­cen­trated, fre­quent and se­ri­ous de­bris flows in China. The re­gion has 341 l arge or medi­um­sized de­bris flow gul­lies.

South­east­ern Ti­bet and western Sichuan have many glaciers, which are sen­si­tive to global cli­mate change.

“Melt­ing ice and snow causes dev­as­tat­ing bursts of glacier lakes and de­bris flows,” said Chen Xiao­qing, deputy di­rec­tor of the In­sti- tute of Moun­tain Haz­ards and En­vi­ron­ment of the CAS.

In 1988, a burst glacier lake and de­bris flow swept away a vil­lage i n Midui gully, i n Ti­bet’s Bomi county, and closed the road for half a year.

An­other huge land­slide and de­bris flow in the Zhamu Creek, Yigong in Bomi county, in 2000, de­stroyed all the bridges, roads and com­mu­ni­ca­tion fa­cil­i­ties built over the pre­vi­ous four decades in the lower re­gion.

This caused di­rect eco­nomic losses of 300 mil­lion yuan and in­di­rect losses of up to a bil­lion yuan.

“Con­struct­ing a rail­way in such a com­pli­cated ge­o­log­i­cal en­vi­ron­ment will face a lot of sci­en­tific and tech­no­log­i­cal dif­fi­cul­ties,” You said. “And the pre­ven­tion and con­trol of moun­tain haz­ards will be key to its suc­cess.”

On the other hand, a large con­struc­tion project travers­ing the re­gion might ag­gra­vate the risks of moun­tain dis­as­ters and en­dan­ger the project it­self.

“We must ur­gently mas­ter the dis­tri­bu­tion pat­tern of land­slides, de­bris flows and other moun­tain haz­ards, and their in­flu­ence on the rail­way project,” You said. “We need to de­mar­cate safe and dan­ger­ous ar­eas, and study how to forecast and pre­vent dis­as­ters.”

In 2014, the CAS be­gan to an­a­lyze the moun­tain haz­ard dis­tri­bu­tion pat­terns and risks, and ex­per­i­ment on dis­as­ter pre­ven­tion along the route.

To date, sci­en­tists have iden­ti­fied the ba­sic dis­tri­bu­tion and ac­tiv­i­ties of moun­tain haz­ards, and set up a data bank of the chal­lenges ahead along the route.

Based on anal­y­sis of the risks, re­searchers of­fered their ad­vice on the route se­lec­tion and tech­nolo­gies to pre­vent and con­trol the land­slides and de­bris flows.

The gov­ern­ment is also plan­ning to build an ex­press­way con­nect­ing Sichuan and Ti­bet. The sci­en­tific find­ings will also be ap­plied in that con­struc­tion.

Ex­perts say t he rail­way and ex­press­way will push for­ward the open­ing up and eco­nomic de­vel­op­ment of Ti­bet.

It will be the most dif­fi­cult su­per project in rail­way con­struc­tion his­tory.” a se­nior en­gi­neer at China Rail­way Eryuan En­gi­neer­ing Group of the Sichuan-Ti­bet rail­way line are tun­nels and bridges

XIN­HUA

LIU KUN / XIN­HUA

Ex­perts from the Chi­nese Academy of Sci­ences take valu­able read­ings from a three-di­men­tional laser scan­ner along the pro­posed route of the Sichuan-Ti­bet Rail­way line.

Xia Lie,

LIU KUN / XIN­HUA

Con­struc­tion staff work in one of the tun­nels, which will be part of the Sichuan sec­tion.

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