School administrators in Fairfax County yesterday began to crack down on a work-to-the-rule job action by county teachers, emphasizing that disruptions in the school academic program will not be tolerated.

Sixty students at Byrant Intermediate School after participating in a sit-in yesterday morning to demonstrate support of the teachers' decision earlier this week to do only work for which they are paid.

"I'm not going to let anything interfere with the learning program of young people," said county School Superintendent S. John Davis.

Davis also said further cancellations of planned after-school activities will have to be announced by area superintendents. Any disruptions, such as the sit-in by 7th and 8th graders at Bryant, "will not be tolerated," he said.

Some student functions usually attended by teachers were canceled this week, and coaches at 24 high schools voted to close gymnasiums after regular school hours.

The actions followed a vote Thuesday by the Fairfax Education Association, a teachers' group, to stop volunteer activities in protest against a 5.15 percent pay raise approved by the county Board of Supervisors. The Teachers are asking for a 9.4 percent raise.

"He [Davis] is forcing teachers into confrontations," said Bob Hicks, president of the FEA, which represents 6,500 of the county's 7,000 teachers. "If he moves into this type of stance, he will create more frustration."

Hicks said several teachers who have been instructed by administrators to perform unpaid tasks "are asking for it in writing, so we will have it on record." He also said he has advised teachers to file written protests. Hicks called yesterday's suspensions "harsh".

The Disciplining occurred after about 300 students gathered in the hallways of Bryant, located at 2901 Popkins Lane in the Groveton area, as classes began at 8:50 a.m.

"The protest is to show that we care about the teachers," said Greg Betterton, 14, an 8th grader.

As the students congregated, a small crowd shouted, "We want a prom." These students mistakenly thought that the prom had been canceled, but were later informed that it would be held as scheduled.

Area Superintendent Herman Howard, along with the school principal and his assistants, told the students to return to class. Most did, including Betterton. The 60 students who refused to return to class were suspended.

"If they [60 students] are suspended, he should suspend all of those who participated," said 14-year-old Tammy Melichar, who participated briefly in the sit-in before returning to class. "I am not saying I wanted to be suspended. But it isn't fair."

Several students interviewed said they support the teachers' job action. Many said they have written letters that they plan to send to school officials, county supervisors and even to President Carter.

School officials said yesterday the majority of Fairfax teachers will receive more than the 5.15 percent pay raise when step increases for length of service are included.

School spokesman George Hamel said 29 percent of the teachers will receive salary increases of 9 percent or more, 41 percent will receive 8 percent raises and 4 percent will receive 7 percent increases. The remaining 26 percent - teachers at top scale - will receive only the 5.15 percent increase.

The county's budget for the next fiscal year will be ratified by the Board of Supervisors on Monday, and a county officials said yesterday he does not expect that county employes, including teachers, will be given larger raises. CAPTION: Picture 1, Bob Jewett, assistant principal at Bryant, tells student to return to class. By James M. Thresher-The Washington Post; Picture 2, Protesting students at Bryant Intermediate School found their names going on a list yesterday.Assistant Principal Bob Jewett wrote down their names. By James M. Thresher-The Washington Post