<?php

$num_arr=array(1,3,6,5,4,2,7,9,5,3,6,2,4,7);

$result = array_reduce($num_arr, function($result, $curr) {
    if (!count($result)) {
        $result[] = array();
    }
    $last =& $result[count($result) - 1];
    
    if (array_sum($last) + $curr > 10) {
        $result[] = array($curr);
    } else {
        $last[] = $curr;
    }
    
    return $result;
}, array());

var_dump($result);