Weylandt was a Belgian rider who died in a crash during the Giro d'Italia in May, clipping a wall during a descent.
Vinokourov wound up in a ditch and was carried up a small bank by an Astana teammate and staff member. They helped him up by putting their arms around him.
As other stricken riders peeled themselves off the ground, Jurgen Van Den Broeck and Frederik Willems, both Belgian riders on the Omega Pharma-Lotto team, and American David Zabriskie of the Garmin-Cervelo team all had to quit.
"This crash came at the front of the peloton in a slippery turn," Schleck said. "The reason so many guys were seriously injured when they went down was because there were no concrete blocks on the right side of the road."
Vinokourov was to be taken by helicopter to La Pitie Salpetriere hospital in Paris for immediate surgery, his team said.
Almost unnoticed in the mayhem was that Contador had crashed for the second time in five days. The three-time defending champion, however, did not point blame, apart from his handlebars.
Contador, who had hurt his right knee during the fifth stage, fell early but recovered to finish the stage in 12th place.
"I had a problem with my handlebars, which knocked into another rider's saddle," Contador said. "The bike hit me on the right knee again. It was a bad day. I was in pain for the whole stage. ... With a bit of ice and rest I can recover."
Voeckler leads Sanchez by nearly two minutes overall. But neither is a Tour contender and will drop in the Pyrenees.
Contador remains 1 minute, 30 seconds behind Schleck in the overall standings, and 1:41 behind Evans — his two biggest rivals, both twice runners-up.
After the rest day, there are two relatively short flat stages before riders enter the Pyrenees on Thursday's 12th stage, with its colossal climb up Col du Tourmalet — one of the Tour's most famed and feared climbs.
That stage is so demanding it could go a long way to narrowing the Tour to a handful of genuine contenders.
AP Sports Writer Samuel Petrequin and Associated Press writer Greg Keller contributed to this report.
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