Formation and rupture of liver hematomas caused by intrahepatic gallbladder perforation:A case report and review of literature

BACKGROUND Gallbladder perforation is a serious complication of acute cholecystitis.Such perforation is a rare but life-threatening situation that can lead to the formation and rupture of liver hematomas.Here,we report a case of a ruptured intrahepatic hematoma caused by intrahepatic gallbladder perforation,and we present a literature review.CASE SUMMARY A 70-year-old male was admitted to the hospital with a complaint of right upper quadrant abdominal pain,flustering and dizziness.The preoperative diagnosis was a ruptured malignant liver tumor,and the patient’s medical images and increased level of carbohydrate antigen-199 suggested that the gallbladder had been invaded.However,the tumor was proven to be a liver hematoma secondary to gallbladder perforation after surgery.The patient was discharged uneventfully on the fifteenth postoperative day.CONCLUSION Intrahepatic gallbladder perforation is difficult to diagnose preoperatively.Radiological examinations play a crucial role in the diagnosis but only for partial cases.Early diagnosis and appropriate surgery are key to managing this rare condition.

Assessing site investigation program for design of shield tunnels

In the design of shield tunnels,it is expected that a design can be more economical as more site investigation data are available.Nev-ertheless,the cost of site investigation will also increase as more site investigation data are required.It is thus important to assess the potential benefit of a site investigation program before it is conducted considering the uncertainty in the soil properties and the site inves-tigation outcomes.In this paper,a probabilistic framework is suggested to assess the effectiveness of a site investigation program for the design of shield tunnels through the random field theory.An efficient method based on the generalized extreme value distribution is used to calculate the failure probability of the tunnel,through which the expected benefit from a site investigation program can be estimated conveniently.The result shows that a site investigation program is more valuable when a greater target design reliability index is needed.The expected benefit from a site investigation program increases as the borehole intensity increases,and it also increases as the scale of fluctuation of the soil properties increases.The method suggested in this paper provides a useful tool for planning borehole layout for the design of shield tunnels,which is promising for the optimization of site investigation.

Machine learning-based prediction of soil compression modulus with application of ID settlement

The compression modulus(Es)is one of the most significant soil parameters that affects the compressive deformation of geotechnical systems,such as foundations.However,it is difficult and sometime costly to obtain this parameter in engineering practice.In this study,we aimed to develop a non-parametric ensemble artificial intelligence(AI)approach to calculate the Es of soft clay in contrast to the traditional regression models proposed in previous studies.A gradient boosted regression tree(GBRT)algorithm was used to discern the non-linear pattern between input variables and the target response,while a genetic algorithm(GA)was adopted for tuning the GBRT model's hyper-parameters.The model was tested through 10-fold cross validation.A dataset of 221 samples from 65 engineering survey reports from Shanghai infrastructure projects was constructed to evaluate the accuracy of the new model5 s predictions.The mean squared error and correlation coefficient of the optimum GBRT model applied to the testing set were 0.13 and 0.91,respectively,indicating that the proposed machine learning(ML)model has great potential to improve the prediction of Es for soft clay.A comparison of the performance of empirical formulas and the proposed ML method for predicting foundation settlement indicated the rationality of the proposed ML model and its applicability to the compressive deformation of geotechnical systems.This model,however,cannot be directly applied to the prediction of Es in other sites due to its site specificity.This problem can be solved by retraining the model using local data.This study provides a useful reference for future multi-parameter prediction of soil behavior.

Analysis of cement-treated clay behavior by micromechanical approach

Experimental results show the significant influence of cement content on the mechanical properties of cement-treated clays.Cementation is produced by mixing a certain amount of cement with the saturated clay.The purpose of this paper is to model the cementation effect on the mechanical behavior of cement-treated clay.A micromechanical stress-strain model is developed considering explicitly the cementation at inter-cluster contacts.The inter-cluster bonding and debonding during mechanical loading are introduced in two ways:an additional cohesion in the shear sliding and a higher yield stress in normal compression.The model is used to simulate isotropic compression and undrained triaxial tests under various confining stresses on cement-treated Ariake clay and Singapore clay with various cement contents.The applicability of the present model is evaluated through comparisons between numerical and experimental results.The evolution of local stresses and local strains in inter-cluster planes are discussed in order to explain the induced anisotropy due to debonding at contact level under the applied loads.The numerical simulations demonstrate that the proposed micromechanical approach is well adapted for taking into account the main physical properties of cement-treated clay,including damage and induced anisotropy under mechanical loading.