Wp Query with multiple custom tag(taxonomy) by get the terms

Try this..

$terms = get_the_terms( $post->ID, 'tag_blogcom' );
    foreach ($terms as $term) {
        $slugs[] = $term->slug;
    }

    $query = new WP_Query( array(
                            'post_type' => 'blogcom',
                            'tax_query' => array(
                                                array(
                                                'taxonomy' => 'tag_blogcom',
                                                'field' => 'slug',
                                                'terms' => $slugs,
                                                ),
                                            ),
                            'posts_per_page' => 10
                            )
                        );

Check the Taxonomy Parameters at WordPress Codex.