是否可以在CURLOPT_URL中包含带URL的变量？

I am storing the Facebook page ID in the variable pageID, and I want the Graph API to retrieve information from these IDs. I am trying to include the variable $pageId with the rest of the URL, however this does not return anything.

Would anyone suggest any alternatives, or whether I am doing something wrong?

  $pageId = substr($_POST["URL"], $pageIdPosition +1);
                        echo $pageId;
                        echo "<br />
";
                        echo "<br />
";
                        // create a new cURL resource
                            $ch = curl_init();

                            // set URL and other appropriate options
                            curl_setopt($ch, CURLOPT_URL, "http://graph.facebook.com/" + $pageId);
                            curl_setopt($ch, CURLOPT_HEADER, 0);

                            // grab URL and pass it to the browser
                            curl_exec($ch);

                            // close cURL resource, and free up system resources
                            curl_close($ch);