Medel piled raft foundation with volume pile + plate element (for lateral loading)

Dear All 

    I have modeled piled raft foundation which piles modeled as volume pile while raft modeled as plate element. To simulate soil - structure interaction, I created interface to both raft and piles. 

In my understanding, correct me if I'm wrong, the connections between raft and piles are not fully rigid since there are interface with reduction of Rinter value between piles and raft. 

How can I make rigid connection between pile and raft?

Thank you.