The ongoing highway-widening project will even open fresh wounds where there could be more “shooting boulders” and landslides. As an engineer in my previous life, I thought, “Could it possible that there is absolutely no solution?” Some random thoughts followed including a suggestion a chillip engineer made to a friend of mine who then made it to me over some coffee – half tunnel!
Studying the area for few minutes and imagining a half-tunnel through, I found it does make sense. Half-tunnels are like ordinary tunnels but with wall on the hill side and no wall on the slope side. If the earth cover over the tunnel is thick, columns are built on the empty side to avoid the roof from collapsing. I have seen such tunnels in the Italian Alps where avalanche are common problem.
Half-tunnels have several advantages. They involve less cost and time to build than the normal full-tunnels. And unlike the full-tunnel that requires stringent safety considerations against fire and tunnel accidents, the half-tunnel having one side open does not present such serious safety issues. Hence, even the tunnel option from Geduchu to Gonglakha, which someone suggested, needs to be to be looked into from this safety perspective.
Once built the half tunnels could present a long-term solution. Any slides or boulders falling off will shoot straight for the valley without falling on the road (see above diagram). It could finally provide the solution to the monsoon nightmare. Therefore some serious studies could be initiated to see the feasibility. True there could be huge short-term construction cost. But these should weighed against the long-term benefits and how much this country is losing, as a whole, in terms of time, resources and manpower every year. With all the talks about climatic change, the need for a long-term solution is even greater.
When the land slide occurs, width of several half-tunnels are wipe out. So if the land itself is not stable, how can a half-tunnel solve the problem?
ReplyDeleteMr. Dorji Wangchuk!
ReplyDeleteThe above HALF TUNNEL is really nice idea! i too feel we must also trade in here in our country. It not only solves the problems from landslides but also looks beautiful.
if we think of 100 years from now, it will be the best solution to have stable and beautiful road.
But, i think it will be impossible here in our country. see, we can't maintain and care our present nasty road even.
Better we have the full tunnel too. It can be made in many places in our coutry.
Whatever, i think the concern authority will forget these half tunnel and full tunnel for Domestic airlines are coming up! At last i feel now we are breeding the HAVES and HAVES NOT.
tashi delek
The problem in the country is not that people don't know what to do, people don't do what needs to be done. People know the problems as well as the solutions. Everyone waits for the "zhung" to do everything.
ReplyDeleteDomestic airline? Although I am from the East, I am not in favour of domestic airlines. I would prefer a double-lane running one from Haa to Tashigang and another one running from Samtse to Daifam. These would make more sense.
But I do feel domestic helicopter service makes sense because the choppers could also be used for disaster management, evacuation of medical emergencies and deployment rapid reaction forces.
nice idea, though. but this very thing about tunnel that too in bhutan where soil quality is not that really good, i dont think it will work. Since underground facilities such as tunnels follow closely the motion of their
ReplyDeletesurrounding soils, landslides and seismic faults can be major causes of the damage
of these underground structures. In other words, these structures can perform well
as long as they are embedded in stable soils. even a slightest crack can cause major damages....in long term these things will become a nuisance...
I think your argument is right for full tunnels but half tunnels can be repaired just like an open highway. Loose soils would require deeper rock bolting and thicker cement grouting. That's why it is costly. But if one considers thousands of man-hours lost every year on the north-south highways, the cost of building the half tunnels would be fraction of such costs.
ReplyDeleteI hear the chief designer for the southern lateral highway is considering the half-tunnel option for landslide areas. Especially between Tala and Kalikhola.
Half tunnels have been employed well in the Italian Alps where avalanche occurs every winter. But as you say the Alps are more stable than the Himalayas.
The basic question is - isn't a shame that even after 50 years we can't stabilise Bhutan's first highway?
well about the word " shame"..its all about engineering quality of ours.i am an architecture student myself...hope in future,,,,we be able to come out with solutions....
ReplyDeleteand yeah, thank you sir for changing ur background colour..
Sorry to intervene this thread mainly contributed by Bhutanese friend.... but could not hold back myself as I like Bhutan & have travelled from Jumja many times in the past....In addition being an engineer (though not in Bhutan for any engg related work), I have following to say....
ReplyDeleteJune 8 thread above rightly mentioned about land being unstable.... He means land below the tunnel and not above. ANy structure needs stable strong support on which it is supported. As everybody knows in last few years, land at Jumja spot has been eroding / giving way considerably and every year the road goes inwards (towards mountain), so the question is if the land below (half pr full) tunnel does get washed away, how will this structure remain in place? I had heard that many high profile engineers from Tala project have spent sleepless nights scratching over this engineering solution. SO, its not as easy as it seems. Had it been (easy), it would have been taken care of long back. However, on the positive side, more complex situations in the world have been tackled successfully so this will also be solved in near future.