how to run a vmdk image on another 64 bit machine which does not have vt support

Seems like it is possible to import VMDK images into VirtualBox, which can run without VT albeit a little slower.

If you either have a very early 64bit chip or are (un)lucky enough (like me) to have a more recent non-VT Intel chip, there's one course of action remaining: EMULATION.

Bochs & Qemu will emulate the 64bit chip hardware, and there are a couple of decent GUI's for managing it. Finding a stable Qemu environment in your preferred distro might entail turning off some chipset features, or backing through some qemu versions or bios binaries.

Bochs is slower than Qemu. Qemu has the fast driver-mode KQemu, but consider it still like running a modern OS on a 200Mhz 1-core processor.