What the city of San Diego is doing now to shore up the landslide area on Soledad Mountain Road in La Jolla was likened by senior engineering geologist Rob Hawk to home construction, only on a massive scale.
"We're putting in sheer pins, large-diameter borings filled with steel and concrete, almost like large nails that are holding things together," said Hawk, about the first phase of construction which began Monday, Oct. 29, 26 days after a catastrophic landslide in the 5600 block of Soledad Mountain Road completely collapsed the thoroughfare, damaging several homes, disrupting utilties and forcing 111 residents to be temporarily evacuated. "We recognize that we can't do anything to the landslide until we stabilize the adjacent area. They're (pins) being put around the westerly side of Soledad Mountain Road surrounding the actual failed portion.
Hawk added, before large masses of earth can be moved, it's necessary "to make sure you've got everything around you stabilized." "That's what we're doing now," he said. "We need to get the landslide stabilized before the winter rains. The landslide moved when it was dry. We don't want to get it wet. It's in a quasi-stable condition and we want to make sure no water gets into it so we can make sure that it stays stable and doesn't cause any additional damage."
In a letter to local residents, the city said Soledad construction work will include drilling a total of 37 holes, 42'' and 48" in diameter, that are 60 to 65 feet deep. Sheer pins will be placed approximately 8 feet on center and will be completely burried underround.
It is anticipatad this first phase of Soledad construction will take up to one month. Workers wil be on site six days a week, 10 hours a day between 7 a.m. and 7 p.m. Hazard Construction Company is the project contractor.
The layered sedimentary soil underlying the landslide area was described by Hawk as a "layer cake" that has been tilted, which might, in part, explain the cause of the landslide. Hawk, however, noted the forensics part, deriving the scientific cause of the landslide from clues found in soils underlying the landslide area, is not his domain. "There are other investigators looking at causal factors," he said. "My job is to repair the landslide and restore the road."
The city has been conducting an underground investigation of the Soledad landslide site, boring deeply into the affected hillside and extracting soil samples for testing. Asked whether any surprises found thus far, Hawk commented: "Just a complete lack of water in the landslide itself."
While the Soledad Mountain landslide site is being shored up by the city, Craig McClellan of the McClellan Law Firm in downtown San Diego is representing about 15 clients on Soledad Mountain Road and Desert View Drive who intend to sue the city of San Diego in the aftermath of the catastrophe.
"They each have separate damages," McClellan said of his clients. "There's two separate categories. One is people that have direct damage to their home, the ones who were red- and yellow-tagged. Then there are the claims of those right next door to those victims, whose homes have suffered a loss in value as a result of the landslide. If they want to sell those homes now, nobody out there is going to want to buy them, certainly not at a price they were worth before the landslide."
Asked whether Soledad Mountain Road residents' location in a known earthquake fault area might work against them, McClellan replied: "Practically everyone in San Diego is in an earthquake fault zone. Rose Canyon (fault) and its tributaries pretty much covers all of La Jolla. There was no activity on the fault that caused or contributed to the landslide. It isn't an earthquake situation."
McClellan also disputes the notion that water underground was not a causal factor in the Soledad landslide. He said underground pipes in the area were old and faulty and the city was remiss in not replacing them earlier, as it has been doing elsewhere in La Jolla.
"These old asbestos pipes were put in there 40 years ago and no preventative maintenance has been done, replacing pipes over the years in this area where landslides have occurred in the past," McClellan said. "The city's priorities were elsewhere. The pipes started leaking in the area and this should have been immediately tended to, and it wasn't. The city just did patchwork and the leaks continued untl the area was totally saturated."
All of the claims against the city by Mt. Soledad homeowners will be filed within six months of the Oct. 3 date of the landslide, said McClellan. Once claims are filed, the city has 45 days to deny them. If the city doesn't deny them, after 45 more days, they're deemed denied by law. "Then you have six months in which to file a suit against the city," said McClellan. "Once the suits are filed, then there's going to be the normal litigation process, discovery, depositions, expert witnesses, etc."
Because there are so many claimants and so many legal issues involved, McClellan noted the Soledad lawsuits against the city could take longer than usual to resolve. "Normally, cases in San Diego are resolved within a year," he said. "This case will probably go beyond that."
What happens after the Soledad landslide site is shored up?
"The next step after that is to restore the land and put the road back," said engineering geologist Hawk.