1. Soft foundation test engineering is a preliminary project primarily aimed at studying the characteristics of soft soil foundations, verifying and improving the treatment design of soft soil foundations, and exploring the construction technology of soft soil foundation engineering. For expressways, first-class highways, and second-class highways on soft soil foundations, test projects should be constructed in advance in accordance with actual engineering conditions, and test results must be obtained before the project fully starts.

2. The research content of the test project should address difficult problems in engineering design and construction, as well as issues that still require research in the introduction and promotion of new technologies, new materials, and new processes.

3. Before construction, a test research outline must be prepared for the test project, a detailed test research plan must be formulated, and engineering design and observation design must be carried out.

4. Site selection requirements
The geological, geomorphological, and engineering conditions of the test project must be representative. The test section should be arranged on the main line as much as possible. If it cannot be implemented on the main line for other reasons, it should be located in an area adjacent to the main line, and the cross-sectional form, dimensions, filling height, and filling materials of the embankment should be consistent with those of the entire project.

The test section should preferably be selected on a straight segment with convenient construction and a small longitudinal slope. The length of each test subsection should not be less than 2 times the base width of the roadbed and not less than 50 m. If test research is conducted on the embankment or artificial structures, the distance between the embankment and the artificial structures should not be less than 2.5 times the base width of the roadbed. In addition, visibility conditions during observation and conditions for setting up observation points should also be considered.

Construction auxiliary roads should not be set on both sides of the embankment in the test section. If unavoidable, it should be ensured that the distance between the auxiliary road and the side ditch of the main line embankment is not less than the base width of the main line embankment, and the connection section between the main line and the auxiliary road should be located more than 500 m away from the observation cross-section.

5. Detailed geological exploration should be carried out for the test project according to the test content and engineering design requirements. Geological exploration should be conducted by combining borehole exploration, sampling tests, and in-situ testing. Geotechnical test items should be determined according to the test research content and engineering design needs, and the results of geotechnical test analysis should be sufficiently reliable and representative.

During the test observation period, depending on the reinforcement situation, in-situ testing techniques such as vane shear tests or standard penetration tests, and cone penetration tests should be used to detect the consolidation status of the foundation soil layers.

In the later stage of preloading, in addition to using in-situ testing for verification, if conditions permit, mechanical drilling and sampling can also be used for testing according to different stratum conditions and treatment schemes to verify the reinforcement effect of the foundation soil layers.

6. The test project should ensure an observation period of at least about one and a half years, and research reports for improving the design and guiding construction should be submitted in a timely manner.

7. Testing instruments, equipment, standard tools, and materials used for processing observation devices should undergo strict selection and screening, have stable and reliable performance, and possess accuracy that meets the test requirements. All instruments and tools for observation should be prepared before the start of the test project.