Can a construction company raise the price of a fixed contract after starting the job?

Where a construction contract does not have a differing site conditions (DSC) clause, the builder/contractor assumes the risk that its performance will cost more than the contract price.  However, where the contract has a DSC clause, a contractor can recover equitable adjustment in construction contract: final work/services different from what is proposed.  Equitable adjustment is available if there is a material difference between the subsurface conditions encountered during the performance of the contract and those set forth in the contract.  The conditions that the contractor found must be reasonably unforeseeable at the time of bidding, and he or she must have reasonably relied upon his or her interpretation of the contract and associated documents.  Furthermore, the material difference between anticipated and encountered conditions must have caused damage to the contractor.  The contract must mention the site condition for the contractor to be eligible for an equitable adjustment.  The recovery would consist of any hike in the cost of performance brought on by the material variations in subsurface conditions.