The Semiconductor Industry Association, which represents the nation's leading independent manufacturers of silicon chips, is expected to file a trade complaint against Japan today, charging that country with blocking imports of U.S. semiconductors.

According to congressional sources, the association intends to file the action with the U.S. Trade Representative under Sec. 301 of the 1974 Trade Act, which empowers the president to retaliate against nations alleged to have unjustifiable or discriminatory trade policies.

The complaint is expected to ask the Reagan administration to negotiate with Japan to open its $8 billion semiconductor market to U.S. manufacturers, and to stop the alleged "dumping" of chips on U.S. buyers at prices below cost.

Sources said the complaint would not recommend restrictions of Japan's access to the U.S. market or suggest retaliatory measures.

The move comes at a time when the nation's major semiconductor companies have been wracked by losses resulting from a dramatic drop in the number of new orders. Companies such as Texas Instruments Corp., National Semiconductor Inc. and Mostek Corp. have all recently announced major layoffs.

Forecasts for global consumption of semiconductors this year have been trimmed from an estimated $26 billion to roughly $20 billion.

Semiconductor manufacturers, several of whom have called for tariff barriers against Japanese semiconductors, want greater access to Japan's market. While the Japanese share of the U.S. market has increased from 8 percent to 18 percent in the last five years, the U.S. share of Japan's semiconductor market has hovered around 10 percent for the past decade, an association spokesman said. In European countries, the U.S. market share reaches 50 percent, he said.

The association said it "is now faced with the reality that a decade of U.S. trade negotiations with Japan in the high-tech sector have failed."

Several members of Congress gave swift support to the association's planned action.

Senate Foreign Relations Committee Chairman Richard G. Lugar (R-Ind.) said, "The evidence that is raised in this complaint raises very serious questions about the entire U.S.-Japan relationship. Toleration of anticompetitive practices in an area like semiconductors, where the U.S. is clearly a world leader, suggests an attitude of dominance out of keeping with our idea of an equal partnership in the Pacific."

Sen. Frank Murkowski (R-Alaska), chairman of the Senate Republican Task Force on International Trade Policy, said, "The fact that U.S. manufacturers consistently outperform the Japanese in neutral markets such as European countries by better than 4 to 1 is strong circumstantial evidence that the allegations of trade barriers in Japan are true."

The object of the complaint is "permitting our sales into the market at a level commensurate with our international competitiveness," said R. Michael Gadbaw, counsel to the association, in response to inquiries.

"We have to convince our government first that there is a problem," said Rep. Edwin Zschau (R-Calif.), who represents the Silicon Valley.

"It's high time we did this," Zschau said of the complaint.