use Illuminate\Support\Facades\DB;

DB::connection()->enableQueryLog();

ここでデータベースへの問い合わせ

$queries = DB::getQueryLog();
dd($queries);

もしくは

\Event::listen('Illuminate\Database\Events\QueryExecuted', function ($query) {
var_dump($query->sql);
var_dump($query->bindings);
var_dump($query->time);
});

https://laravel.com/docs/5.0/database#query-logging
http://laravel-tricks.com/tricks/display-all-sql-executed-in-eloquent#comment-2655309790