A 21-year-old North Carolina man who fell asleep in a Northern Virginia woman's bed after raping her repeatedly over three hours was sentenced yesterday to life in prison for rape and given 30 more years on other charges growing out of the incident.

Fairfax County Circuit Court Judge Johanna L. Fitzpatrick imposed the sentences on Michael Johnson, 21, telling him the woman he assaulted "was treated with particular cruelty."

Johnson had pleaded guilty to rape, sodomy, burglary and maiming in the Nov. 2 attack on a 35-year-old teacher. He was arrested by officers who said they found him sprawled asleep on the woman's bed in her garden apartment in the Falls Church area.

The woman had managed to inch her way out of the bed and escape from Johnson 15 minutes after he fell asleep, said prosecutor Chanda Myers.

"The effect of this on me as a person has been devastating," the victim told Fitzpatrick during yesterday's sentencing. "I live with a constant sense of fear and several times daily things will happen that raise that to a level of panic. It's just always there."

Johnson, a resident of Gaston County, was visiting a relative who lived across the hall from the victim. He forced his way into the woman's apartment with a butcher knife after the woman answered the door and opened it a crack after seeing Johnson through the peephole and apparently mistaking him for his relative, the prosecutor said.

He then forced her into the bedroom at knifepoint and repeatedly raped and sodomized her, according to court testimony. Several times during the attack he threatened her with the knife, Myers said the victim told her. She suffered several cuts on her hands and the back of her neck, witnesses said.

Shortly after the attack began, a policeman knocked on the apartment door after neighbors reported hearing screams, Myers said. Johnson allegedly refused to let the woman answer the door and the officer apparently left without further investigation, Myers said.

The woman later realized the man had fallen asleep when she heard the knife clatter to the floor, Myers said.

"She remembered it takes about 15 minutes to go into a deep sleep," Myers said the woman told her. "She very slowly turned her head and opened her eyes and watched the lighted clock near the bed."

Myers said the victim told her: "It seemed like forever."

When 15 minutes had passed, she inched her way from beneath the man's arm and leg and ran for help.

Johnson's court-appointed attorney, Steven A. Merril, asked the judge to "give this defendant mercy," but noted that Johnson deserved "a long sentence."