You are in london so is this heavy clay that has dried out in this drought?

yes it is, can you imagen!!!, this part of garden has been abandon since long time, i decided to invest it, since it is lay in front of my kitchen.
acctully , there is trees in this part of land (plums), so might be the roots , cause this regidity?

Well if its heavy clay and tree roots- in this draught you have got a job on. There are clay breakers you can buy plus grit and compost etc which can be dug in But I think you might have to wait till its wet before trying to dig it and also have the frost to help you break it up? A photo would help so we can see the tree situation? My garden is clay and parts of it are like concrete and I spend my life adding improvers/grit and compost and parts are much better now.

Unless you're saying you can't dig because you're physically incapable, Ehsanray, just wait - the only digging that can be done in drought conditions on clay is with a pick axe, so leave it until the drought's over and the autumn rains come, that area will soften up, and if the weather allows, you should then be able to dig it or turn it over in October or November, or wait till early spring and tackle it then. Trouble with clay in London, depending on how bad it is, when it gets really wet its impossible to work because it sticks to your garden fork (I know this from experience here!) in great clods - if its as bad as that, leave it till its dried out a little, then tackle it, and while you're digging, incorporate lots of horticultural grit and any humus rich material you can get hold of, like composted horse manure, soil conditioning compost from the garden centre, leaf mould, spent mushroom compost, anything like that. The more you put in, the better the soil will get. And if you find it utterly impossible to dig it over, you could try removing any major weeds and grass by digging those out separately, then just dump the above mentioned materials on it, spread them out with a rake, and wait for the worms to work it into the soil. Do that in autumn rather than spring though, but its only if you're desperate because it will take a good year for any difference to be noticeable in the soil.

thanks for your reply, but could you please look at the updated pictures, to see the condition of this area.
the last picture show you how i am trying to solve the problem, i spend 30 min, to dig the land after i watering it to make it soft, the i remove the soil, to treat it and mix it with fertilizeres, and good condition compost.

Looks to be well compacted, as if its used to lots of foot traffic - that would make it very difficult to dig.

This looks solid - do you really need to dig this EHS? As the tree is already there - have you considered putting down a frames filled with bark or pebbles on top of a membrane? and then add some pretty planted pots on it?