You are an excellent literary reading assistant. Please help me summarize the main points of the content of the following text in 200 words or less in Chinese: These problems  limit the application and utilization of VP in the engineering projects.  The feasibility of EO for the soil improvement has also been proved  (Lefebvre and Burnotte, 2002; Micic et al., 2001; Peng et al., 2015; Wu  et al., 2016), in which the pore water flows from the anode towards the  cathode when subjected to the electric current in the soil. As the water is  removed from the consolidation system, the soil properties are improved  with decreased water content and increased shear strength. Research  has been completed that uses the EO to improve marine clay (Rittirong  et al., 2008; Wu and Hu, 2014; Xue et al., 2015). Kaniraj and Yee (2011)  performed laboratory tests on the organic soil that was strengthened  using EO combined with chemical stabilization. The use of EVDs with  the reduced pumping interval could improve the efficiency of the EO for  organic soil. Flora et al. (2017) utilized EO to strengthen the fine-grained  dredged sediment, with the increased soil yielding strength. Hu et al.  (2019) experimentally investigated the effects of soil pH and ionic  species on the EO for the kaolin. These studies also indicated that the  application of EO was limited due to excessive energy consumption and  severe electrode erosion, which need to be addressed for improving its  efficiency (Zhang, 2018; Zhang et al., 2017).  A few methods were reported to explore the combined utilization to  solve their disadvantages (Chang et al., 2010; Chien et al., 2015; Huang  et al., 2021; Liu et al., 2020b) and further improve the consolidation  efficiency for marine clay. Peng et al. (2015) developed a combined  method of electro-osmotic grouting with vacuum drainage at the cath ode and conducted experimental test to examine the efficiency in  improving the soil properties. Zhang et al. (2017) carried out experi mental tests and filed studies that examined EO combined with chemical  grouting for marine clay. This study indicated that the electro-osmotic  chemical treatment is a useful technique for clay improvement and the  efficiency was influenced by the concentration of the salt solution. Liu  et al. (2014) developed a new technique that combined EO, VP, and  surcharge preloading for the ground improvement. Zhang and Hu  (2019) proposed EO and VP using electrokinetic geosynthetics, to  improve the kaolinite properties and demonstrated its ability to increase  the water removal efficiency. As suggested in these studies, the com bined method is a promising technique to strengthen marine clay and  solve various geotechnical issues for the soft foundation (Chien et al.,  2015; Liu et al., 2020a).  This study developed a combined method of vacuum preloading with  electro-osmotic consolidation to improve marine clay. A prefabricated  device was designed to efficiently combine the EO and VP and facilitate  the combined method for the construction practices. Laboratory tests  were conducted to evaluate behavior of the treated soil and investigate  the effectiveness of the combined method for marine clay. The proper ties of the treated soil in the terms of water removal efficiency, shear  strength, and bearing capacity were examined to provide an optimal  combination for marine clay.  2. Laboratory experiment  2.1. Soil properties  The marine clay with black-gray color which had low bearing  capacities was collected at an average depth of 2 m from the Xinyang  Port, Yancheng, Jiangsu Province, China, and used in the laboratory  tests. Before laboratory tests, physical tests were conducted to measure  mechanical properties of the soil samples. The material properties, as  listed in Table 1, were the results of disturbed soil samples. The soil  parameters indicated that the collected soil was the silty clay with high  organic compounds. Based on the X-ray diffraction analysis, quartz is the  primary part for the soil organic matter with approximately 60.71%  SiO2. The fine grain percent of the soil reached up to 87.93% (12.76%  clay grain and 75.17% silt grain), and the soil sample exhibited a high  cation exchange capacity. To ensure the same conditions for three tests,  the untreated soils were mixed with the designed amounts of water in  the test tank to create the remolded soils。