The phrase 'gradually accumulated' is correct and usable in written English.
You can use it to describe the process of collecting something over a long period of time. For example: "The antique shop owner had gradually accumulated an impressive collection of valuable items over the past two decades."
Overspray in the painting bays gradually accumulated on the tracks and skids on which vehicles rested while they were painted.
It's only with hindsight that we can say that these features gradually accumulated to the point at which we have something recognisably human.
This costs either £1.49 or 150 gold to enter, the latter being an in-game currency gradually accumulated through completing challenges and winning games.
"Lost and Found," the set opener, began with a bass vamp and gradually accumulated density, with a melody superimposing five beats over four.
As more bona fide uses led to a medical revolution — X-rays for medical imaging, radium for killing rapidly dividing cancer cells — hints of danger gradually accumulated.
Marine sediments gradually accumulated in the deepest parts of the basin, and large reefs composed of marine fossils and algae formed along its margins.
The department has gradually accumulated more power since swallowing up the then separate Department of Economic Affairs in 1969 – which had been set up five years earlier by Harold Wilson to split finance and economic policy.
Proteomic information of rice grains in the anthesis, ripening, and maturing stages under heat stress has been gradually accumulated.
Also, the shoreline at Young-Jin beach was extended by about 2.4 7.6 m seaward, and seabed sand was gradually accumulated around areas covered by the geotextile tube.
These changes are gradually accumulated in specific chromatin environments as cell differentiation progresses and reflect different features and functional states of B cells.
In conclusion, brief co-culture of porcine oocytes with spermatozoa gradually accumulated in the MFSS chamber improved the efficiency of producing monospermic fertilized embryos and blastocysts.
