RESUMO
The tandem compound piles are a combination of a granular column in the deep section and a concrete pile in the shallow section. This method effectively utilizes the consolidation and densification effects of the granular column, as well as the cementation strength of the concrete material. The granular column acts as a consolidation path, aiding in the densification of the surrounding soil. On the other hand, the concrete pile prevents the bulging deformation that commonly happens in granular columns during field construction. To study the bearing capacity and deformation of the improved foundation with tandem compound piles, a coupled continuum-discrete numerical model was developed in this study. The accuracy of the model was confirmed by comparing its results with experimental measurements. Additionally, a parametric study was conducted, considering three influential factors: (1) cushion thickness and modulus, (2) length, modulus, diameter, and spacing of the tandem compound pile, and (3) soil modulus. The results indicated that reducing the cushion thickness and increasing the cushion modulus allowed the pile to bear more loads. Moreover, increasing the length and modulus of the deep section of the pile reduced deformation and improved the bearing capacity. The pile modulus, however, had a limited effect on enhancing the bearing capacity. It is important to maintain a critical pile spacing of at least twice the pile diameter. Finally, a high modulus of the underlying stratum led to higher vertical and radial stresses in the pile.
RESUMO
BACKGROUND: With advances in medicine, there have been more and more ways to treat renal calculi in recent years. Percutaneous nephrolithotomy (PCNL) is a safe and effective treatment. The purpose of this paper is to study the efficacy and safety of PCNL combined with negative pressure suction in the treatment of renal calculi by meta-analysis. METHODS: The PubMed, EMBASE, Cochrane Library, Chinese Journal Full-Text Database, VIP, Wanfang Science and Technology Journal Full-Text Database, and Chinese Biomedical Literature Search databases were searched for articles related to the efficacy and safety of PCNL combined with negative pressure suction in the treatment of renal calculi from the establishment of the databases to October 2021. Endnote X9 software was first used to check and eliminate the articles, and the quality of the included articles were evaluated according to the risk of bias tool of Cochrane Collaboration. Stata 15.1 software was used to record the data. A meta-analysis was performed on the stone clearance rate, operation time, postoperative complications, postoperative fever, septic shock, intrapelvic pressure, and blood loss of PCNL combined with negative pressure suction in the treatment of renal calculi. The reliability of the results was assessed by a sensitivity analysis. Egger's linear test was used to test the publication bias of the articles. RESULTS: A total of 10 articles were included in the meta-analysis, and the total sample size of the study was 820. The meta-analysis showed that when PCNL combined with negative pressure suction was used to treat renal calculi, the stone clearance rate and the occurrence of septic shock of the test group did not differ significantly from that of the control group; the incidence rate of postoperative complicationsãthe operation time, the intraoperative bleeding and the postoperative fever of the test group was significantly better than that of the control group. DISCUSSION: Compared to the group without negative pressure, PCNL reduces the operation time, postoperative complications, postoperative fever, septic shock, and intraoperative blood loss without increasing the risk of septic shock.