You can change as follows in your controller itself…
array('allow', // allow authenticated user to perform 'create' and 'update' actions
'actions' => array('create', 'update', 'GenerateExcel', 'GeneratePdf', 'GenerateExcelCustom', 'GenerateMultiplePdf', 'export', 'popgeneral', 'uvview', 'delete', 'view', 'picdelete', 'csv', 'irisdelete', 'DeleteUV'),
//'users' => array('@'), // Comment this line
'expression' => '(Yii::app()->user->role== "admin" || Yii::app()->user->role == "Trial Leader" )', // Here give your session conditions like you can add more arrays expressions...
),