When Virginia Gov. Charles S. Robb goes before the 1985 General Assembly Wednesday night, it seems certain that his initiatives will be overshadowed by an issue that has defied solution: the state's troubled prison system.

With statewide races for governor, lieutenant governor and attorney general already under way, the corrections problem also appears likely to spill from the 46-day session into a campaign headache this fall for many of Robb's fellow Democrats.

"The major issue with respect to corrections is going to be political," said Del. Richard C. Cranwell of Roanoke, a leading house Democrat. All 100 seats in the House of Delegates are up for election this year and Republicans hope to add to their 34 seats, some using prisons as an issue.

Cranwell and others agree that the legislature is certain to earmark millions of dollars from the state's $160 million surplus for corrections. But, Cranwell said, "nothing we are going to do" will erase the bad publicity that Robb and his administration have suffered as a result 1984's prison escapes, riots and related controversies.

While most politicans agree that prisons will be the dominant issue for the 1985 session, the state's 140 legislators will confront such controversial questions as highway funding, which could strain relations between urban and rural legislators, rights of the handicapped, education, and voter registration.

Robb, beginning his fourth and final year as governor, has kept many of his legislative proposals secret, prefering to announce them on the assembly's first night during his State of the Commonwealth speech, and in a budget message on Thursday.

"This is a short session," said George M. Stoddart, Robb's press secretary. "The biggest bill obviously is going to be the budget amendments to continue funding his priorities . . . pumping it into education and economic development."

The Republicans, hoping to play a more visible legislative role, are planning a news conference before Robb's speech to give their version of the State of the Commonwealth, an event that in the past has followed the governor's speech and received little attention.

It is likely that the Republicans will focus on the prisons issue, which has captured much of the attention of the public during the past year, first with the May 31 escape of six death row inmates from the state's maximum security prison at Mecklenburg County, and with disturbances there and escapes at other prisons.

In November, Robb's third correction director resigned, and his replacement, Allyn R. Sielaff, already has angered some legislators by what they see as heavy-handed tactics to run the troubled Department of Corrections.

"The Democrats have a problem," said Senate Minority Leader William A. Truban (R-Shenandoah). "Where does the buck stop? It has to stop with Robb, not because he caused [the problems], but because he's the chief."

Robb, the son-in-law of President Johnson who is thought by many to have national political ambitions, is expected to propose more money for corrections in an effort to shore up what politicians see as the major shortcoming of his administration.

Some legislators speculated that Robb may propose seed money for a new prison in his corrections package, a move that would revive potentially divisive debates over where such a prison would be built.

Richmond legislators are anxious to close the state penitentiary, but some corrections experts say that the state must build its new prisons near urban areas if they are to have access to the workers and services needed to run them.

The good news for Robb, who would prefer to highlight his education initiatives and a growing economy, is that he will present the assembly with a budget surplus of about $160 million. He will ask the lawmakers to appropriate even more funds for education and grant a long-delayed pay increase for the state's workers that is expected to cost about $80 million.

"When you give 80,000 people a pay raise, that's a pretty good campaign start" for Democrats, said Truban.

Robb's top aides are trying to salvage his highly touted bill to guarantee the rights of handicapped citizens against employment discrimination and to reduce bureaucratic hurdles for handicapped persons dealing with the state.

That bill, introduced in the 1984 session with great fanfare by Robb's administration and pushed by Del. Warren G. Stambaugh (D-Arlington), was significantly watered down after business interests expressed strong opposition.

Asked whether Robb's lame duck status could hinder his programs, state Sen. Joseph V. Gartlan Jr. (D-Fairfax), who has been critical of the prison problems, said that Robb "obviously fits the definition of lame duck, but it's not all that burdensome."

Gartlan and Truban noted that Robb will prepare the $17 billion 1986-88 budget that will go to the legislature in early 1986, though he will leave office before it is enacted.

"He's still got an awful lot of leverage in state government," said Gartlan. Under Virginia law, Robb cannot succeed himself.

"Governor Robb is not going to send down a lot of bills," Truban agreed, "but he still makes appointments. He's still the governor. The power is going to start slipping away."

In addition to budget amendments and prisons this year, major issues the General Assembly will grapple with include rewriting the state's complex highway funding formula into one that that urban legislators hope will give them millions more in highway construction dollars.

That question, delayed by the assembly's leaders for several years, tops the agenda of legislators from Northern Virginia and other urban areas, where officials say that worsening traffic problems affect their ability to attract lucrative industries.

"We in the rurals will fight it if they start beating us over the head, but the votes are begining to go urban," said Truban.

On environmental issues, legislation to approve uranium mining in Southside Virginia and to remove restrictions on a proposed 400-mile coal slurry pipeline are being hotly contested again among some of the state's leading businesses. Railroad lobbyists, opposed to the pipeline, won a key victory last week when a legislative subcommittee voted to oppose use of water in any pipeline -- action that could make the proposed coal slurry impractical.

New moves are expected on several other holdover issues.

Proponents of tougher drunk driving laws are expected to try again to raise the state's legal drinking age for all alcoholic beverages to 21. It currently is 19 for beer and wine.

Robb supported the higher age limit in 1983, but he abandoned it last year for tougher laws on determining when drivers are to be declared legally drunk. Federal moves to encourage states to adopt 21 as the legal age limit could improve the measure's chance this year.

A move may be made to adopt mandatory seat belt legislation similar to New York's, but many legislators give this little chance.

Another perennial issue already filed is a measure to require a tax on nonreturnable drink bottles, sponsored by state Sen. Madison R. Marye (D-Madison County).

"The bottle bill is back again, and we're opposed to it again," said Virginia Chamber of Commerce lobbyist John Broadway.

Robb's press secretary said that the governor probably will propose a new measure to increase voter registration. During his 1981 campaign for governor, Robb supported mail registration. But he has backed away from that position since his election, much to the disappointment of blacks and critics of the state's standing in national voter registration rankings.

Robb appointed a commission on voting that last month urged several reforms but refused, on a 7-to-7 vote, to endorse mail registration in favor of allowing state agencies, such as motor vehicle offices, to act as satellite registrars.