devi spedirli come stringa:

codice:
<script>
$(document).ready(function()
{
data = '{"user":"ciccio","surname":"bello","Email":"cicciobello@dominio.it"}';
data2 = '{"mykey":"123456","Object":"user","Operation":"myoperation","Version":"1"}';
$.ajax({
		chache: false,
		type: "GET",
		url: "http://mysrv.test/api/myfile.axd",
		dataType: "json",
		data: "data="+data+"&data2="+data2,
		success: function(msg){
                 $.each(msg, function(key,state) {
			     alert(state);
		       });	
		},
        error:function(XMLHttpRequest,status,error){
			alert("Error: "+error);
		}
	});

});
</script>