Yes, much research goes into string theory, but its predictions are "not even wrong", they cannot be proven false by experiment [1].
Disclaimer: I'm a layman on the topic, this is just repeating what I've heard.
[1] https://www.amazon.com/Not-Even-Wrong-Failure-Physical/dp/04...
As @jerf points out here as well, LCG has as much experimental support as any of the other competing GUT hypotheses... which is to say, none. This whole "thing" about the lack of experimental support and lack of testable / falsifiable assertions in physics (especially String Theory) is explored at length in two pretty interesting books: Not Even Wrong[1] by Peter Woit and The Trouble With Physics[2] by Lee Smolin.
[1]: http://www.amazon.com/Not-Even-Wrong-Failure-Physical/dp/046...
[2]: http://www.amazon.com/The-Trouble-With-Physics-Science/dp/06...
Lost in Math - Sabine Hossenfelder[2]
The First Three Minutes - Steven Weinberg[3]
Hyperspace - Michio Kaku[4]
Not Even Wrong - Peter Woit[5]
The Trouble With Physics - Lee Smolin[6]
About Time - Paul Davies[7]
Time Reborn - Lee Smolin[8]
The Elegant Universe - Brian Greene[9]
The Hidden Reality - Brian Greene[10]
The Fabric of the Cosmos - Brian Greene[11]
Quantum Space: Loop Quantum Gravity and the Search for the Structure of Space, Time, and the Universe - Jim Baggott[12]
The Universe Speaks in Numbers: How Modern Math Reveals Nature's Deepest Secrets - Graham Farmelo[13]
Three Roads To Quantum Gravity - Lee Smolin[14]
Programming the Universe: A Quantum Computer Scientist Takes on the Cosmos - Seth Lloyd[15]
Higgs - The invention and discovery of the 'God Particle' - Jim Baggott[16]
[1]: https://www.amazon.com/Something-Deeply-Hidden-Emergence-Spa...
[2]: https://www.amazon.com/Lost-Math-Beauty-Physics-Astray/dp/15...
[3]: https://www.amazon.com/First-Three-Minutes-Modern-Universe/d...
[4]: https://www.amazon.com/Hyperspace-Scientific-Parallel-Univer...
[5]: https://www.amazon.com/Not-Even-Wrong-Failure-Physical/dp/04...
[6]: https://www.amazon.com/Trouble-Physics-String-Theory-Science...
[7]: https://www.amazon.com/About-Time-Einsteins-Unfinished-Revol...
[8]: https://www.amazon.com/Time-Reborn-Lee-Smolin/dp/0544245598/
[9]: https://www.amazon.com/Elegant-Universe-Superstrings-Dimensi...
[10]: https://www.amazon.com/Hidden-Reality-Parallel-Universes-Cos...
[11]: https://www.amazon.com/gp/product/0375412883/ref=dbs_a_def_r...
[12]: https://www.amazon.com/Quantum-Space-Gravity-Structure-Unive...
[13]: https://www.amazon.com/Universe-Speaks-Numbers-Reveals-Natur...
[14]: https://www.amazon.com/Three-Roads-Quantum-Gravity-Smolin/dp...
[15]: https://www.amazon.com/Programming-Universe-Quantum-Computer...
[16]: https://www.amazon.com/Higgs-invention-discovery-God-Particl...