Research On Quick Reinforcement And Its Effect Assessment Of Karst Foundation For Leiyang Station Of Wuhan-Guangzhou High-Speed Rail Way

Some high-speed railway will pass through the area with poor geological conditions, such as karst, in high construction of high-speed railway in china. The high-speed railway is characterized by high Smoothness, so it is a key index for the settlement after construction to evaluate high-speed railway.Once the karst diseases occurs, it is hard to treat it, especially for high-speed railway, because of its short period of treatment and difficulty of construction.So the researches on how to treat it quickly, the reasons of karst diseases, and the mechanism of diseases are meaningful to practices and to present the measures of treatment.The disease mechanism of karst foundation for special worksite of passenger dedicated line is investigated combined with the survey data and investigation data. It is prelimilarily reported that three reasons lead to diseases.The one is in geological survey, which is not enough to get the karst size, distribution, and structure feature. The other is in design, which deviates from the capacity of karst. Another is in construction, which disturbs the existing structure.The measure of reinforcement for special worksite of passenger dedicated line is introducted detailly including the pressure pouring, churning pile, and low pressure pouring for embankment.Combined with the construction of foundation reinforcement, the calculation theory of settlement of post-construction is analyzed, and the applicability of the composite foundation method applied in this project is explored. The modulus method of composite foundation is adopted in calculation of the settlement with better reinforcement effect and the jet grouting is constructed directly to the bedrock. The calculation results meet with the field monitoring data.The simulation models according to three resprestative sections are established with the sigma/w module of geo-slope software, the parameters of which are chosen reasonably. Then, the calculation results show that the collapseof cave cause the significant impact on settlement of subgrade and the reinforcement is effective.The field test is conducted combined with the construction of reinforcement, the results of field test show that the settlement is over the allowable value of specification, while the rate of variation is very small. Therefore, the field monitoring should be continued for a period of time.