Insertion et suppression dans un tableau multi-dimension

$cpt = 0;

while($row = mysql_fetch_array($result))
{
	$tableau[$cpt][0]=$row['debut'];
	$tableau[$cpt][1]=$row['heure_fin'];
	$tableau[$cpt][2]=$row['idtype_temps'];
	$tableau[$cpt][3]=$row['num_dossier'];
	$tableau[$cpt][4]=$row['duree'];
	$cpt++;
}

function tab_insert($tab,$ligne,$indice)
{
	global $tab;
	$tab1 = array_slice ($tab, 0, $indice);
	$tab2 = array_slice ($tab, $indice);
	array_push ($tab1, $ligne);
	$tab = array_merge ($tab1, $tab2);
}

tab_insert($tableau,$ligne,2)

function tab_insert($tab,$val,$indice) 
{
	$tab_ini=array();
	$tab_unique=array();
   	for($n=0;$n<count($tab);$n++) 
   	{
	 	$tab_ini[]=serialize($tab[$n]);
   	}
   	$val = serialize($val);
   	$tab1 = array_slice($tab_ini,0,$indice);
	$tab2 = array_slice($tab_ini,$indice);
	array_push($tab1,$val);
   	$tab_ini = array_merge($tab1,$tab2);

   	for($n=0;$n<count($tab_ini);$n++)
   	{
	 	$tab_unique[]=unserialize($tab_ini[$n]);
   	}

   	foreach ($tab_unique as $key => $row)
   	{
	 	if (!is_array($row))
	 	{
			unset($tab_unique[$key]);
		}
   	}
   	return $tab_unique;
}