"substantially failed" is correct and usable in written English.
You can use it to indicate that something failed to an extent that is beyond what is usually expected. For example: "The project substantially failed despite the resources that were devoted to it."
The EU, the US and even the World Bank all substantially failed to meet their commitments according to an Oxfam report released earlier this summer.
The two plaintiffs, Children's Rights of Manhattan and the Center for Child Advocacy at the University of Connecticut School of Law, filed the request after a report issued in August found that the agency substantially failed to meet the standards of a 1991 court settlement in areas like providing proper mental health and dental care for children in state custody.
Utilizing the values for the calcium-dependent time constant of activation from Arreola et al., [77], or even changing them substantially
I'm all in favor of universal health care, but if the plan doesn't reduce costs substantially, it fails to solve the problem.
Both sides say the reimbursements have failed substantially to increase the ability of Pakistani forces to mount comprehensive counterinsurgency operations.
(AP) HARDY WANTS SHORTER BAN The swimmer Jessica Hardy will try to have her possible two-year suspension "reduced substantially" after a failed drug test cost her a spot on the United States Olympic team.
"Tottenham's offers failed substantially to reflect Saido's true value while the timing made no allowance for our own recruitment of a suitable replacement for a proven Premier League goalscorer.
In addition, viable and non-viable spores failed substantially to activate pro-inflammatory gene expression by 6 h post-infection (h.p.i). in both infection models.
Mr. Du, the environmental official, dismissed suggestions that Beijing had failed to substantially reduce harmful pollution.
In the United States, McDonald's Monopoly game promotion and Mighty Wings limited-time offer met internal expectations but failed to substantially lift results because of intense discounting.
In a second round of bidding for Starrett City, eight groups submitted bids Tuesday that were substantially lower than a failed $1.3 billion offer made last year for the working- and middle-class enclave on Jamaica Bay in Brooklyn.
