Effects of Cone Penetrometer Testing on Shallow Hydrogeology at a Contaminated Site

Penetration testing is a popular and instantaneous technique for subsurface mapping, contaminant tracking, and the determination of soil characteristics. While the small footprint and reproducibility of cone penetrometer testing makes it an ideal method for in-situ subsurface investigations at contaminated sites, the effects to local shallow groundwater wells and measurable influence on monitoring networks common at contaminated sites is unknown. Physical and geochemical parameters associated with cone penetrometer testing were measured from a transect of shallow groundwater monitoring wells adjacent to penetrometer testing. For wells screened above the depth of cone refusal, the physical advancement and retraction of the cone had a significant effect (p < 0.01) on water level for several pushes within 10 meters of a monitoring well, and a measured increase in specific conductivity. No effect on geochemistry or water level was observed in continuous monitoring data from wells screened below the depth of cone refusal, but variability in specific conductivity from these wells during penetration testing was only a fraction of the natural variation measured during precipitation events. Continuous measurements of specific conductivity and water level demonstrated that the effects of penetration testing have limited spatial and temporal distributions with a null effect post-testing.

Pelatihan Pengujian In-Situ Tanah bagi laboran Muda Mekanika Tanah

In-situ test adalah salah satu metode pengujian geomekanika yang pelaksanaannya dilakukan langsung di lapangan, tanpa pengambilan percontoh untuk laboratorium. Rendahnya minat laboran dalam mendalami bidang mekanika tanah khususnya pengujian tanah baik di lapangan maupun di laboratorium. Hal ini di sebabkan oleh para laboran menganggab bahwa pengembangan keahlian dalam menggunakan peralatan pengujian dan pengolahan data mekanika tanah cukup sulit dan mahal. HIMATESI merupakan sebuah himpunan mahasiswa yang beranggotakan para peneliti muda, laboran muda atau mahasiswa tingkat akhir yang sedang melakukan penelitian dan pengujian mekanika tanah. Mitra menyadari perlu peningkatan pemahaman tentang pengujian In-Situ tanah. Namun disisi lain menjadi ketakutan tersendiri bagi mitra tentang penyelsaiaan permasalahan yang timbul dalam pengujian In-Situ tanah pada saat pelaksanaan dilapangan. Perguruan tinggi menjawab persoalan mitra dengan memberikan pengetahuan tentang pengujian In-Situ tanah dan pelatihan penggunaan peralatan pengujian In-Situ tanah serta trik-trik menhadapi permasalahan dalam pengujian In-Situ tanah pengujian In-Situ tanah secara gratis. Kegiatan Pengabdian masyarakat dalam bentuk pelatihan pengujian In-Situ Tanah bagi laboran mekanika tanah yang diadakan bertujuan untuk memberikan bekal informasi tentang tentang pengenalan dan penggunaan alat pengujian In-Situ seperti Dynamic Cone Penetrometer, alat Handbore dan alat Sandcone. Hasil pelatihan ini mampu meningkatkan pengetahuan peserta terhadap penggunaan alat pengujian In-situ tanah dan trik-trik dalam mengatasi permasalahan dilapangan terhadap penggunaan alat Insitu sehingga diharapkan para peserta dapat mengimplementasikan ilmu yang di dapat dalam pelaksanaan dilapangan nantinya.

Comparison of the liquid limit of loess defined by the Vasiliev and Casagrande test methods

The paper compares liquid limit values obtained by the Vasiliev and Casagrande apparatus in line with BDS 648:1984 and BDS EN ISO/ TS 17892–12:2018, on the basis of testing 25 silty loess samples. The results indicated that compared with the Vasiliev apparatus, the Casagrande apparatus gives a higher liquid limit. An equation allowing conversion of the liquid limit obtained by the Vasiliev cone penetrometer to the liquid limit by the Casagrande apparatus has been developed.

Correlation between the liquid limit of clay derived by the Vasiliev and Casagrande test methods

The liquid limit is one of the most commonly used index properties of soils. The paper compares liquid limit values determined by the Vasiliev cone penetrometer method and by the Casagrande cup method, based on 45 natural clay samples collected from the Kozloduy Town area (North Bulgaria). An empirical correlation based on these liquid limit results has been derived.

Evaluasi Variabilitas Kinerja Struktur Perkerasan Jalan Berbasis Pengujian Seismik

Evaluasi perkerasan jalan diperlukan untuk memeriksa kerusakan awal yang terjadi pada perkerasan. Penilaian perkerasan dilakukan untuk memprediksi kualitas material perkerasan secara fungsional dan struktural. Penelitian ini bertujuan untuk menilai dan mengevaluasi perkerasan jalan secara struktural menggunakan pengukuran seismik Spectral Analysis of Surface Waves (SASW). Metode SASW menguji sifat material perkerasan sebagai teknik evaluasi struktural. Metode SASW merupakan metode seismik non-destruktif yang menghasilkan, mengukur, dan memproses gelombang Rayleigh yang terdispersi. Selanjutnya, proses inversi dengan teknik optimasi digunakan untuk menganalisis data dispersi gelombang Rayleigh guna menghasilkan profil kekakuan setempat, dalam parameter kecepatan gelombang geser dan modulus elastisitas. Parameter kekakuan dari metode ini yang dihasilkan pada tingkat regangan mikroskopis yaitu kurang dari 0,001%, di mana pada tingkat ini, bahan tanah berperilaku elastis linier. Hasil dari uji SASW selanjutnya dibandingkan dengan uji Marshall dan nilai uji Dynamic Cone Penetrometer (DCP). Pengamatan visual juga dilakukan untuk menentukan penilaian fungsional untuk mengukur seberapa besar kerusakan permukaan jalan. Hasil penelitian menunjukkan bahwa metode SASW dapat secara efektif mengukur kecepatan gelombang geser dan variabilitas modulus elastisitas pada setiap lapisan perkerasan. Studi ini merekomendasikan pengujian seismik untuk memeriksa variabilitas kinerja struktural perkerasan jalan terpasang.

Comparison of California Bearing Ratio (CBR) Value Based on Cone Penetration Test (CPT) and Dynamic Cone Penetrometer (DCP)

In civil engineering, land is important because as a place for building infrastructure to be built, so that the building infrastructure on it is stable, adequate carrying capacity is needed. The amount of soil bearing capacity can be determined in several ways, including the California Bearing Ratio (CBR) Field Test, Cone Penetration Test (CPT) and Dynamic Cone Penetrometer (DCP). The CBR and DCP tests are often used to determine the level of surface soil density on road structures, while CPT is usually used to determine the hard soil layer on the building structure. However, in certain situations Sondir and DCP data are often used to predict the CBR value, because the test is quite practical and efficient compared to the CBR test. CBR testing requires heavy equipment which in most small-scale projects is not available. In this study, we compared the CBR value based on the data obtained from the Sondir and DCP tests. Data collection was carried out in Surakarta and its surroundings. Based on the test results, the CBR value generated from the DCP test tends to be smaller than that from the CPT test with a ratio of 0.62: 1. This study resulted in the relationship between CBR values from the results of the CPT and DCP tests shown in the following equation: CBR (DCP) % = 0.2552 CBR(CPT) + 2.6306 and CBR (DCP) % = 0.617 CBR(CPT).