Rockslide on TA-J’lem highway was preventable, experts say

Boulders were "as big as kitchen cupboards," according to driver whose car was totaled.

By SHARON UDASIN
311_ J'lem traffic (photo credit: Marc Israel Sellem)
311_ J'lem traffic
(photo credit: Marc Israel Sellem)
For a driver whose car was destroyed on Sunday night when a rockslide suddenly showered his vehicle with huge rocks on Road 1, escaping without a scrape was nothing other than “luck.”
“Suddenly you are inside a rain of stones – you don’t see it coming and it goes on for less than a second,” said the driver, who asked to remain anonymous. “Fortunately enough, it fell one meter before the car and not on the car.”
Driving at 80 to 90 kph on the main Tel Aviv-Jerusalem highway, the driver said that both his car and another about 20 meters away instantly ran over boulders “as big as cupboards,” but that a gap behind them prevented other vehicles from slamming into them.
“I managed to break down only about 100 meters after the avalanche,” he said, adding that the stones tore apart his tires and damaged the engine underneath. “I just slipped on along the road – there were no tires.”
The incident, which the took place near the Hemed Interchange outside Abu Gosh and stopped inbound Jerusalem traffic for hours, was probably preventable, according to an expert engineer. He added that such incidents were rare in Israel.
“If the fence had a strong foundation as it should have had, the entire event could have been prevented,” said Dr. David David, a soil engineering consultant.
The fence barricading the cliff that collapsed has no foundation at all, according to David, which caused the wire mesh to rotate in the direction of the road after being bombarded by the falling rocks. But the rockslide itself was triggered by an erratic geological event that happens approximately every 10 years, he explained. While the cliffs that line this area of Road 1 are primarily composed of hard limestone, they also contain layers of soft chalk, which drop down every decade or so at certain locations – usually with a push by something like groundwater or rainfall, David said.
A stronger barrier – such as mesh that blankets the entire rock bed and has a foundation, rather than simply fencing off the area – would help prevent such a drop, according to David.
“This event is something that you can prevent more and more – you can reduce the occurrence of such events by refining the meshes,” he said.  But the driver whose car was destroyed disagreed.
“Even if it’s iron, a net can’t stop this,” he said. “There were pillars, and they were bent down like paper. Only a cement wall could hold it, maybe not even that.”
David stress that this event “is a reminder to avoid a more serious occurrence.
“This is a story of slopes all over the world, and authorities should improve safety on long roads and in mountainous areas,” he said.
Both David and a colleague, Dr. Ram Ben-David, said the public works organizations are currently making a serious effort to improve rocky roadside conditions.
“The roads are facing problems of stability so now [the Israel National Road Company] built a team that includes me as a geologist to solve problems,” said Ben-David, a geological engineering consultant, who is working with David on the team.
Ben-David said that he and his team members have been examining roadside “geological formations” all over the country “and the possible reasons for instability, and then the engineers are planning solutions.”
Some particularly problematic locations that the group is currently working on include a stretch of Road 40 as well as a spot on Road 65.
Meanwhile, as far as Road 1 goes, engineers are taking slope stability into careful consideration as they move forward with plans to expand the entire highway, according to Ben-David.
“Each case is a different case according to geology and to height,” Ben-David said. “There are many factors involved in solving the problem. First of all, you must be aware that the problem exists, and then you must plan according to civil engineering.”
Some solutions among a wide range of possibilities he cited were building retaining walls, refining mesh barriers as David explained, building anchors and “sometimes reducing the topography.”
“We are all a team working on these kinds of issues and the company is very much aware and acts to solve the problems,” he said.
But to prevent events such as Sunday night’s happening again, Ben-David stressed that people working in the field – such as road cleaners – should pay careful attention to any seemingly dangerous areas.
“They should be aware of problems – they should report to their superiors and then they need to react and to put in place budgets and plans,” he said. “But road events like this one are not that common in Israel.”
However rare, the driver maintained that the incident could have injured many people.
“We were very lucky, because during a busy day on this road, a lot of people could’ve been killed,” he said. “What amazes me the most is that after they cleared the road they just let traffic move on.”