UPDATE 1-Komatsu Q1 profit soars as China sales double

* Komatsu profit jumps 76 pct, biggest since March 2011 qtr

* China sales jump, Joy Global acquisition boost revenue

* Komatsu keeps f'cast for annual profit fall on acquisition costs (Recasts, adds China revenue figures)

TOKYO, July 28 (Reuters) - Japan's Komatsu Ltd said first-quarter profit surged on a global recovery in demand for earth-moving equipment led by a 'dynamic' expansion of sales in China.

Global construction companies are riding a new wave of Chinese demand helped by infrastructure projects, a housing boom and increased investments linked to China's modern-day "silk road."

Komatsu's quarterly operating profit jumped 76 percent to 52.4 billion yen ($472 million) from the same period a year earlier, its biggest profit increase in more than six years - also helped by the acquisition of a U.S. mining equipment rival.

The result surpassed a forecast for 30.5 billion yen by Okasan Securities.

Revenue in China, its fastest growing market, soared 104.5 percent.

Caterpillar this week beat estimates and raised its full-year forecast for the second time, helped by a steady recovery in demand in China. It was the clearest indication yet that the U.S. firm is turning a corner after weak commodity prices and global economic uncertainty hurt orders for earth-moving equipment over the past few years.

Komatsu's domestic rival, Hitachi Construction Machinery Co , said on Thursday that it has also seen stronger demand in China, propelling a near seven-fold surge in its quarterly operating profit.

Komatsu shares have risen around 10 percent so far this year on hopes of a global recovery in demand.

The company maintained its forecast for a 10.4 percent fall in annual operating profit to 156 billion yen due to costs related to last year's acquisition of U.S. rival Joy Global. ($1 = 110.9700 yen) (Reporting by Naomi Tajitsu; Editing by Edwina Gibbs)