[jQuery] How to prevent incremental ajax requests?

[jQuery] How to prevent incremental ajax requests?

Hi all. I'm using this very simple script to load remote content inside a div:
$(document).ready(function() {
    $("#frm :input:visible:enabled:first").focus();   
    $().ajaxStart($.blockUI).ajaxStop($.unblockUI);
    $('.carrega').click(function(){
        var row = this;
        row.abbr = row.abbr + "qtde=" + $('#qtdeLotes').val();
        $.ajax({
            url: row.abbr,
            cache: true,
            dataType: 'html',
            success: function(data){
                var $conteudo = trim12( data );// load content
            }
        });
        return false;                   
    });
 });
Very simple and very crazy. In my first click to load content works fine. In the second click jquery get 2 requests. And so on... What's wrong?
Cheers