function ul_ol_func( $content ) {
$content = str_replace('<ul', '<ul class="ul-list"', $content);
$content = str_replace('<ol', '<ol class="ol-list"', $content);
return $content;
}
add_action( 'ul_ol_hook', 'ul_ol_func' );
<?php echo do_action('ul_ol_hook', $tblock_textarea); ?>
...
add_filter( 'ul_ol_hook', 'ul_ol_func' );
<?php echo apply_filters('ul_ol_hook', $tblock_textarea); ?>