Virginia's Democratic Gov. Charles S. Robb unveiled plans today to grant state classroom teachers two 10 percent pay raises, costing $73.5 million, and to restore 36,000 people to the state's Medicaid rolls--all without raising taxes.

Making his first formal proposal to the House Appropriations Committee, the new governor told legislators they could pay for his proposals while staying within the balanced $13.1 billion budget presented to them by former Republican governor John N. Dalton. Some $143.5 million could be saved by cutting back on higher education funding and through cost-savings from his proposed freeze on hiring state employes, Robb said.

His announcement, which capped a week of intensive political negotiations among Robb, the state teachers association and senior Democratic leaders, underlines Robb's campaign pledge to improve Virginia's poorly rated primary and secondary schools.

The Robb proposals call for an increase in the average teacher salary in Virginia of 10.1 percent in each of the next two years, reaching an average of $21,417 by 1984, virtually matching the present national average. They do not, however, spell out any mechanism for ensuring that local school districts actually spend the funds on teacher salaries.

"The real problem is what we can do to target the money to teacher salaries," said Robb at a press conference later. "That is not an easy objective to be accomplished."

"During the past several decades, you have been in the pleasant position of being able to expand services and add programs in each budget," Robb told the committee. "But we now face harder, different times, and we must make harder, different choices . . . . Our next budget must commit all of state government to live within diminished means."

Robb called on the legislature to use that $143.5 million he hopes to save to:

Reinstate 36,000 of the 51,000 poor people that the Dalton administration had proposed dropping from the state's Medicaid rolls, and spread the burden of the Reagan budget cuts among state health care providers, including hospitals, pharmacies and nursing homes.

Provide for performance-based salary increases for state employes. Robb stopped short of urging across-the-board cost-of-living raises.

Allocate $9 million for a spending package that would include $127,000 a year to promote the use of Dulles International Airport, $580,000 in human services to make up for federal budget cuts, a youth job program and the accelerated opening of two new state prisons.

One of the biggest budget cuts included in Robb's package, some $38.8 million, would come in higher education, primarily at colleges like George Mason University that have seen what Robb called "uncontrolled growth" in enrollments over the last few years. Virginia Education Secretary John T. Casteen III said the cut would reduce anticipated teaching and research positions, but would not mean layoffs for university personnel.

Representatives of the Virginia Education Association, one of the earliest and strongest supporters of Robb's campaign last year, reacted with guarded enthusiasm to Robb's pledge of higher teacher salaries. "We would have liked to see him go the whole way, but he did put it first on his list of priorities," said Walter J. Mika Jr., president of VEA. "I can't be too disappointed at this point."

Their enthusiasm was dampened, however, by questions about whether Robb's $73.5 million increase would actually make its way to teachers' wallets if it does win the approval of the legislature. Under Robb's proposal, the funds would be conveyed to local school districts through the state's basic aid formula, and could not be earmarked specifically for teacher pay increases.

The teachers had lobbied hard over the last few weeks for the state to place the money into an "incentive fund" to be set aside specifically for salaries, and Robb had initially agreed to go along. But subsequent lobbying by leaders of the House Appropriations and Senate Finance committees, in concert with local school officials, apparently changed his mind.

Although the Robb program calls for the restoration of some medically needy people to the Medicaid rolls, his administration is planning a series of extensive cuts to bring soaring Medicaid costs in line. But Secretary of Human Resources Joseph Fisher said the Medicaid changes would not include limiting eligibility for admittance to nursing homes, a Dalton proposal that prompted widespread public outcry.

Among the proposals considered to curtail Medicaid expenses are the elimination of Medicaid subsidies for eye and foot care, discontinuation of coverage for children between the ages 18 and 21, and a reduction in nonemergency hospital stays.

Robb proposed to fund merit raises and increased health benefits for state employes by cutting the state's personnel funds 2 percent to account for positions left vacant by normal turnover and attrition, for a savings of $55 million. That reduction would not trigger any layoffs, Robb said.

Democratic legislators were generally receptive to Robb's proposal, particularly to his decision not to seek new general tax increases in a year when members of the House of Delegates are up for reelection.

But his failure to endorse a $96 million increase in corporate taxes, recently passed the Senate by overwhelming margins, is likely to put him at odds with some Senate leaders. Both Sen. Edward E. Willey (D-Richmond) and Senate Majority Leader Sen. Hunter B. Andrews (D-Hampton) have said publicly that Virginia needs the new revenues to weather the effects of the recession and Reaganomics.

"We remain hopeful we won't need it," said Robb yesterday of Willey's corporate tax measure. "I will do everything I can to avoid a tax increase but I cannot categorically repudiate it because there are compelling needs we have to consider."