Mayor Marion Barry yesterday proposed increasing D.C. government spending by $164.3 million in fiscal 1986 -- including more funds for schools, mental health services, job training and emergency assistance and shelter -- without a tax increase and despite a probable freeze on the federal payment to the District.

District officials are counting on continued improvement in the economy and reduced unemployment to generate additional revenue for new programs without having to raise D.C. tax rates, as was done during the current fiscal year.

Barry's proposal, which must be approved by the City Council and Congress, includes $900,000 in capital spending to finance a comprehensive study of facilities at the city-run Lorton Reformatory in southern Fairfax County.

The study could pave the way for new construction or changes in the size or shape of the prison, which has been troubled by problems of crowding and violence. However, Barry insisted the study is not directly related to a push by federal officials to build a new regional prison in the District.

The mayor is seeking a total of $2.27 billion in spending during the fiscal year that begins Oct. 1, or an 8 percent increase over the current year's budget.

Barry also proposed a 1986 capital improvements budget of $240 million, or more than double the amount budgeted for the current year. Much of the new money would be earmarked for repairs and resurfacing of city streets and bridges and other improvements of "infrastructure."

This year's budget contrasts sharply with those of other recent years, when austerity was the key word and the mayor proposed cutting back on a number of aid programs and ending a general public assistance program serving more than 5,000 physically disabled persons a month, a plan the City Council quashed.

The mayor yesterday proposed substantial increases in social services and job programs. He also included some new initiatives to prevent drug abuse, particularly of PCP; to shelter homeless youths, and to create a youth services team to investigate allegations of sexual abuse of delinquent youths.

The proposed budget includes several new programs for senior citizens, including a seniors' job hotline and a new shelter for abused seniors. Under a new "respite program," trained helpers would go into the homes of families caring for terminally ill patients or those with Alzheimer's disease to relieve them for a few hours or days of 24-hour-a-day vigils.

Barry proposed a new $4 million business purchase assistance program, under which the city would buy run-down buildings in selected commercial corridors, such as H Street NE, and sell them to District residents for $1 if they promised to fix them up and use them for businesses.

The budget includes an additional $4 million to fund a new Economic Development Finance Corporation to provide loans to minority businesses.

The budget requests an increase of $2.8 million for corrections and estimates that the District's average daily prison population will rise by 266 to 6,050. The police and fire departments would receive $3.9 million each in added funds, largely for pay increases, replacement of equipment and two new emergency ambulance units.

At a news conference, Barry pledged he would balance the new budget "without new taxes or increased tax rates." Last year, he sought tax increases totaling $44.2 million to cover increased spending. The council eventually approved a tax increase of $31 million.

The mayor said he had considered recommending a reduction in taxes in place of the spending increases, but concluded that the additional "support programs" were more important.

"I have not heard any outcry from our citizens that they want to reduce taxes at the expense of people," he said.

The mayor claimed credit for improvements in the District's finances and budget controls that have provided a "strong foundation for home rule's second decade" and paved the way for the city's maiden entry into the bond market last year.

"I am proud of our record of four consecutive years of budget balance," Barry said. "We have made enormous strides since 1979."

The mayor's proposed budget includes spending increases of $18.8 million for the Board of Education, $19.5 million to cover increased salaries and benefits for city workers, $13.8 million for St. Elizabeths Hospital and other mental health-care services, $4.8 million for emergency assistance and shelter, and $1.9 million for additional day-care services.

Barry said that he anticipates that city property assessments will go up only slightly in the coming year, averaging 4 to 5 percent for residential property and 8 to 9 percent for commercial property.

Despite the mayor's euphoria over the improved economy, city officials are concerned that President Reagan's efforts to reduce federal aid to cities; force the District to increase its contribution to the federal Civil Service Retirement System, and freeze the fEderal payment could foreshadow serious problems for the city.

The District has enjoyed steady growth in the federal payment over the past four years. For the current 1985 fiscal year the city received a federal payment of $425 million, as well as a one-time payment of $32.2 million for special crime prevention initiatives, mental health programs and expenses connected with last month's presidential inauguration.

Reagan will recommend in the budget message he sends to Congress next week that the federal payment, which reimburses the city for services provided to the federal government and is a substitute for property tax revenues on federal property, be kept at $425 million, city officials said. This would reduce the federal share of the operating budget from 20.5 percent in fiscal 1985 to 19 percent.

Barry told reporters that he "did all I could" to argue for an increased payment, but that officials of the Office of Management and Budget (OMB) argued persuasively that if they gave in to the city they would have to give in to others, leading to an "unraveling" of their austerity efforts.

"It's a good point," Barry said.

City Council Chairman David A. Clarke said yesterday that he generally approved of Barry's budgetary thrust, including adequate funding for programs like general public assistance and medical charities that the council has insisted upon.

However, Clarke criticized Barry for failing again to include funds in the budget to help further reduce the city's accumulated deficit, which currently stands at $270 million. During the past two years, the council has amended the mayor's budget proposal to include funds for deficit retirement.

"It is of utmost importance to our growing financial reputation that we make a commitment to annually setting aside funds to retire that deficit," Clarke said. "And it appears that, in fiscal 1986, the council will again have to amend the proposal" to do so.

Under legislation passed in Congress last year, management of St. Elizabeths mental hospital is to be transferred from the federal government to the District government by October 1987.

The city is to develop a comprehensive mental health-care system with St. Elizabeths as a part of it by 1991, and this will require more District funding than in the past, since the hospital has been funded largely with federal dollars.

The fiscal 1986 budget would increase District funding for mental health services and the hospital by $13.8 million, or an 8.7 percent raise. This will be used largely to expand community programs for former St. Elizabeths patients, who are being moved out of the hospital as quickly as possible.

Other additions will pay for more day-care slots for children of working low-income parents, more shelter beds for the homeless, a 10 percent increase to 15,700 in the number of emergency assistance grants for persons who need help paying rent or utility bills, foster care for 40 more children, and room for 100 more mentally retarded persons at District facilities.

The city would fund 11,405 summer jobs for youths under this budget in the summer of 1986, compared with 9,980 funded this year. The number of participants in other jobs programs for youths and training programs for both youths and adults with dependents would rise by 740 to 4,735.

The mayor also said he would propose using $900,000 for a new antidrug-abuse program focusing on PCP. The details of the program are to be worked out with the City Council, he said.

The city projects that 1985 will be a year of "continued but slowed economic growth," following a year in which the D.C.-resident work force grew by 18,800, personal income rose at a 6.2 percent annual rate and inflation continued at moderate levels.