E21D 9/001
Improving soil or rock
Official title: {Improving soil or rock, e.g. by freezing; Injections (for sinking shafts E21D1/10; injection of liquids for binding dust E21F5/18; improving or preserving foundation soil or rock E02D3/00; borehole closures, i.e. packers, for use during the injection process E21B33/12)}
E21D9/001 (Improving soil or rock) appears on 62 US grants and 35 published applications in this corpus.
Search patents in E21D- Granted patents
- 62
- Published applications
- 35
- Assignees
- 64
- Inventors
- 216
- Latest grant
- 21 Apr 2026
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1976 | 5 | 0 |
| 1977 | 2 | 0 |
| 1978 | 2 | 0 |
| 1979 | 1 | 0 |
| 1980 | 0 | 0 |
| 1981 | 3 | 0 |
| 1982 | 0 | 0 |
| 1983 | 3 | 0 |
| 1984 | 3 | 0 |
| 1985 | 0 | 0 |
| 1986 | 1 | 0 |
| 1987 | 1 | 0 |
| 1988 | 0 | 0 |
| 1989 | 1 | 0 |
| 1990 | 4 | 0 |
| 1991 | 0 | 0 |
| 1992 | 3 | 0 |
| 1993 | 0 | 0 |
| 1994 | 2 | 0 |
| 1995 | 1 | 0 |
| 1996 | 0 | 0 |
| 1997 | 2 | 0 |
| 1998 | 3 | 0 |
| 1999 | 0 | 0 |
| 2000 | 0 | 0 |
| 2001 | 0 | 0 |
| 2002 | 0 | 1 |
| 2003 | 0 | 2 |
| 2004 | 1 | 1 |
| 2005 | 2 | 0 |
| 2006 | 0 | 0 |
| 2007 | 0 | 1 |
| 2008 | 0 | 0 |
| 2009 | 0 | 1 |
| 2010 | 2 | 1 |
| 2011 | 0 | 1 |
| 2012 | 0 | 0 |
| 2013 | 0 | 0 |
| 2014 | 0 | 0 |
| 2015 | 0 | 0 |
| 2016 | 0 | 0 |
| 2017 | 0 | 1 |
| 2018 | 2 | 3 |
| 2019 | 1 | 3 |
| 2020 | 3 | 0 |
| 2021 | 0 | 6 |
| 2022 | 3 | 2 |
| 2023 | 3 | 6 |
| 2024 | 1 | 1 |
| 2025 | 5 | 3 |
| 2026 | 2 | 2 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
Subgroups
Granted patents
Recent patents
- Static crushing directional anchor withdrawal method at end of large-mining-height working face21 Apr 2026US 12,607,121 B2Huating Coal Group Co., Ltd.
- Method for recovering residual coal pillars by Freezing water accumulated in room-and-pillar mining area10 Mar 2026US 12,571,308 B2Taiyuan University of Technology
- Method and system of underground deployment of materials and equipment23 Sep 2025US 12,421,682 B2hyperTunnel IP Limited
- Methods for real-time deviation monitoring of miniature pipe roofing jacking pipe of spiral soil-discharging19 Aug 2025US 12,392,609 B2Cccc First Harbor Engineering Co., Ltd.
- Method and system of constructing an underground tunnel5 Aug 2025US 12,378,884 B2hyperTunnel IP Limited
- Co2 trans-critical freezing system and freezing method18 Jun 2026US 2026/0168726 A1China Coal Special Drilling Co.,Ltd.
- Pressure-controlled tunnel directional grouting-based reinforcement devices16 Apr 2026US 2026/0103981 A1China University of Mining and Technology
- Construction method and system for roof sealing and foundation strengthening of crossing project in high-density urban area18 Sep 2025US 2025/0290415 A1University of Science and Technology Beijing
- Methods for real-time deviation monitoring of miniature pipe roofing jacking pipe of spiral soil-discharging17 Jul 2025US 2025/0231026 A1Cccc First Harbor Engineering Co., Ltd.
- Method for recovering residual coal pillars by freezing water accumulated in room-and-pillar mining area22 May 2025US 2025/0163804 A1Taiyuan University of Technology
Most cited
By later US patents
- Ground freezing method54US 3,943,722 AUnion Carbide Canada Limited · 1976
- Process for reinforcing geological formations48US 4,113,014 ABayer Aktiengesellschaft · 1978
- Process for stabilizing rock and coal formations by bonding these formations to themselves or other geological formations25US 4,452,551 ABASF SE · 1984
- Method of strengthening geological formations21US 4,715,746 ABayer Aktiengesellschaft · 1987
- Method and apparatus for grouting of tunnel liners19US 5,645,375 A1997