aoColumns is not working

Instead of passing the value like

{'bSortable': false},null,null,null,null,null,null,null,null,null,null,null,null,null,{'bSortable': false} 

in aoColumns can I pass a string which is also containing the same value as above.
My Code is like:

var excluded_clmns_sorting = $('#sorting_val').val();
//the above variable returns {'bSortable': false},null,null,null,null,null,null,null,null,null,null,null,null,null,{'bSortable': false}.
var oTable = $('#data-table').dataTable( {
       "sDom": 'CT<"clear">firtlip',
       "oTableTools": {
            "sSwfPath": basePath+"/js/extras/TableTools/media/swf/copy_csv_xls_pdf.swf",
            "aButtons": [ {"sExtends": "csv","sFileName" : curpath+".csv","sButtonText": "Save to CSV","mColumns": "visible"} ]
         },
       "aoColumns" : [excluded_clmns_sorting]
 } );

In js Console it is showing nCell is undefined.
if I pass array in excluded_clmns_sorting variable and doing the following code:

 var excluded_clmns_sorting = $('#sorting_val').val();
    var excluded_clmn_sorting = (excluded_clmns_sorting) ? excluded_clmns_sorting.split(",") : [];
    $.each(excluded_clmn_sorting, function (i) {
      excluded_clmn_sorting[i] = (excluded_clmn_sorting[i]);
    })

    var oTable = $('#data-table').dataTable( {
       "sDom": 'CT<"clear">firtlip',
        "oTableTools": {
            "sSwfPath": basePath+"/js/extras/TableTools/media/swf/copy_csv_xls_pdf.swf",
            "aButtons": [ {"sExtends": "csv","sFileName" : curpath+".csv","sButtonText": "Save to CSV","mColumns": "visible"} ]

         },
         "aoColumns" : [excluded_clmn_sorting],
         "aoColumnDefs": [{
                            "bVisible": false,
                            "aTargets" : excluded_clmn
                         },
                      ],
        "iDisplayLength": 10,
       'sPaginationType': 'full_numbers'
    } );

Then in js Console it is showing only oCol is undefined.

Please guide me how to resolve this issue.