Mains water pipe question

[cubix]

Hello everyone
Can anyone tell me what the official name is for the Grey wavin like pipe in the back ground that is been used to carry mains water into the block of apts. IT looks like its a 4"(100mm) pipe, due to the fact it has to carry mains pressure(in this case there is also 4pumps on site) how are joints made so as not to leak. Also can anyone tell me what the strap on bracket (like a boss) is called. IT doesn't look like the best way to tap off a mains to feed a core of apts. In this case it seems like the bolt's holding the clamp on had worn and broken, I presume to a mix of water presure and being buried under ground. Is it not possible to get a piece of main's pipe with an upstand built in which you clamp your hydra-dare feed pipe onto, if that makes sense?.
Just to add are the bolts normally like this (wedged like)

Cheers

 

[oldplumber]

the boss you show works fine until the bolts you show have corroded away and the boss drops off. hence wedge shaped corroded bolts. good to see the supply is now lying in the mud and openly contaminating your apartment supply, dont advise you call your water supplier until you have made good the problem. take yor bits to your merchant and get them to supply the equvalent parts required or suggest an alternative

 

[cubix]

Not my job OP so I will leave it to the plumber to call the water board. As I say just curious is there not a better way/longer lasting way of connecting a hydra-dare off a mains feed as this development is only about 10-12 years old. IF all the connections on this main feed go like this it will be some fun replacing them as most of them are 5 feet down. This one was interesting trying to find as we kept on finding various hydra-dares.